fixed FPE in computeLevelsetPositive when SUMABS=0 (still not sure what
this stuff is useful for, though :-))

Use the new Fl::delete_widget() call to delete widgets in callbacks
in FLTK 1.1.6. FLTK 1.1.5 introduced a potential crash due the fact
that it could access a widget's data after its callback was executed.
Fl::delete_widget() in 1.1.6 delays the deletion until the next
Fl::wait() call. In any case, this means that we cannot use
group.clear() anymore.

make Export_LcField also work with SimplexBase

better solution for offset

fine-tune epsilon

better epsilon

update to latest gl2ps

fixed error checking code to work also with adaptive views.

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

Added GUI for z-clipping plane distance factor (and changed the
default value from 10 to 5)

New "fast" routine to create simplices used only for
visualization. This speeds up the load time of large tetrahedral
(volume) meshes by roughly 50%, and brings Read_Mesh.cpp pretty close
to mshsort.cpp performance-wise. Since Read_Mesh does many more things
(all the Tree/List queries to create elementary/physical entites +
partitions), this is actually pretty good.

Loading a 1.4 million tets mesh file on my 1.5 GHz Linux machine now
takes about 17 seconds.

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).

Revert to GL_NORMALIZE instead of GL_RESCALE_NORMAL (since GL_RESCALE_NORMAL
is not supposed to work with anisotropic scalings)

cleanup variable names

use homogenous coordinates so that we can apply translations, too.

older versions of g++ don't like static members in inline fcts...

set lc=0.1 by default, since the default viewport size is of order 1

Better interactive point creation (modified patch from schumact@colorado.edu)

- 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

- 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

fix gcc warning

pretty print

GUI::reset_option_browser() should not show() the whole option window,
just the appropriate group

cleanup (and remove 2 shift/reduce conflicts in parser)