The "Simplex" class is now derived from a new class "SimplexBase",
which contains only pointers to the nodes, and none of the other stuff
necessary for the actual mesh generation.

All the input/output/display routines have been rewritten in terms of
SimplexBase: this provides a gain of almost 50% in memory when you
just load meshes from .msh files to do visualization stuff, instead of
actually generating the mesh.

doc update

New General.ClipFactor option to fine-tune the position of the near and far
clipping planes (default = 10; setting a smaller value leads to a better
z-buffer resolution, but zooms/rotations can then lead to undesired clipping).

- First draft (pretty much untested!) of new "Integrate" plugin to
  * integrate scalar fields over all the elements in a view
  * integrate the circulation of vector fields along line elements
  * integrate the flux of vector fields across surface elements

  Used with Plugin(DisplacementRaise) and Plugin(Evaluate) this
  permits for example to compute the area/volume of deformed
  configurations; and, with Plugin(CutPlane)+Plugin(Skin), the
  perimeter of deformed sections. Another interesting application is
  to use it on a vector field with Plugin(CutPlane), in order to
  compute fluxes across arbitrary cross-sections.

- Added "connectPoints" option to Plugin(CutParametric) so
  that we can feed its output to Plugin(Integrate)

- Added Normals and Tangents options to visualize the orientation of
  elements in post-processing views

- Added "swapOrientation" in Plugin(Transform) to change the
  orientation of the elements (in place) (+ moved the transformation
  routines from the view class into the plugin)

- fixed #defines in some of the plugin header files

New Plugin(HarmonicToTime)

New (very simple, but very nice IMHO) callback mechanism in plugins: a
plugin can now set the min/max/step in input fields, and draw
arbitrary stuff when the values are modified.

This makes the plugin interface MUCH nicer: the plane in CutPlane is
defined interactively (a la "Clipping planes"), the sphere in
CutSphere is visible, the min/max values in CutMap reflect the min/max
in the view, etc.

- make the rotation matrix a matrix of doubles (instead of floats)

- store the modelview and the projection matrices in CTX

- new unproject() routine to transform window coordinates to model
  coordinates

- cleaned up all the static variables in the Opengl_Window class

- small fix to reduce normal clamping when zooming

The new "External data source" option makes the "Vector type->Raised
view" unnecessary. Just select "Vector type->Displacement" and choose
the data source from any other view in the list--including "Self"!

added small option to color the arrows representing a vector field
according to the data from another view

new solver options: SocketCommand and NameCommand (patch by
<C.Stott@surrey.ac.uk>)

Generalized "Raised scalar view" vector type: one can now also raise
vector and tensor views. (It's now simply called "Raised view".)

1.56

complete WriteView in parsed format (print strings)

added ability to save views in "parsed" format

FLTK >= 1.1.5 is now required to compile Gmsh: the FL_Scroll widget in
FLTK < 1.1.5rc1 is buggy (clear() destroys the scrollbars)

Thanks to Nicolas for the bug report !

- removed the sort view list stuff: it's a bad idea since we re-sort
the list in many places when we search/replace through it

- add a simple "set visibility->all on/off" switch

added ability to sort the list of views (by name, by visibility)

- the main menu is now scrollable when there are more than 25
buttons and it can handle an arbitrary number of buttons (this removes
the "100 views max in the GUI" limitation)

- the view number is now also displayed in the menu (to make it easier
to find the view when one has many many views)

- added "Remove empty views" menu item

For all our mechanical engineering friends out there, I just cleaned up the stuff
I did with Sean last year, i.e., allow to draw a vector field as a displacement
map, with another scalar field displayed instead of the displacement norm.

It's basically the same as Plugin(DisplacementRaise), but it does not modify the
actual data inside the view (so e.g. you cannot save it). Instead, it's implemented
as an alternative "Vector display" mode. This allows to easily animate deformed meshed
with arbitrary scalar fields drawn on them. (The GUI for this is kinda lame, but
it works: just select Vector display->Raised scalar view, select the scalar view
number, et voila.)

I also generalized the smooth normal code path a little, so that we can have smooth
normals for vector-as-displacement and tensor-as-von-mises plots, too.

minor text mods

better label for "constrain bg mesh"

- fixed a couple of corner cases in the computation of 2D/3D isos
  (+renamed the routines)
- fixed small box size bug in the GUI

airplane work: reorganized the option panels in the GUI (more descriptive
labels, same categories for geo/mesh/post, etc.)

generalized + added GUI for clipping planes

- moved the smooth normals stuff into a separate file
- added smooth normal support for surface meshes (very nice!)

- Triangle now supports our background meshes

- fixed memory leak in Optimize_Netgen (forgot to free the volume
  vertices) + added missing 2nd order reset

- fixed a couple of typos in the docs

1.54.1

fixed old extrusion mesh generator (used the old 99999 volume hack!)

- All extrusion commands now return a list of 2 numbers (instead of 1):
  the first, as before, is the number of the "top" of the extruded region
  (i.e., a point for extrude point, a line for extrude line, ...), the
  second is the number of the "body" of the extruded region (i.e., a
  line for extrude point, a surface for extrude line, ...).

- "Extrude Surface" now always creates a new volume (automatically),
  EVEN WHEN THERE IS NO LAYERS SPECIFICATION. This makes it consistent
  with "Extrude Point" and "Extrude Line", which always create new
  curves and surfaces, respectively.

  Important Note: you will have to modify your old .geo files to avoid
  duplicate volume definitions if you use "Extrude Surface" without
  extruding the mesh (i.e., without the "Layers" command). These
  duplicate volumes would be harmless, but they would srew up your
  physical volume definitions later on...

  * Solution 1: use the new volumes (recommended). To do this, just
  remove your old extra volume definitions and let Gmsh create the
  extruded volumes for you. (To retrieve the volume number created by
  Gmsh, use "aa[] = Extrude Surface {...};;": the volume number is
  "aa[1]".)

  * Solution 2: keep the old volumes.

  a) clean way: retrieve the new volume number (aa[] = Extrude Surface
  {...};;) and delete the new volume with "Delete { Volume aa[1]; }"

  b) dirty (but handy) way: since, in order to create the new volumes
  with the less impact possible, Gmsh uses "low" numbers (actually,
  forcing "Geometry.OldNewreg=0") for the new volumes, just remove all
  "low number volumes". For example, if you have 4 "Extrude Surface" in
  your file, you can then just do "Delete{ Volume {1:4}; }"

Voila :-)

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