added small warning in automatically generated opt_* files

- fixed double free in case there is an error in tSprintf

- new StrRelative command

- small demo on how one can add a generic title to a plot using
  Plugin(Annotate)

added a 5th axes mode: "Ruler" to help measure distances between any two
points

a little more work on the axes stuff: enable global axes for the geometry and
the mesh, too. We can finally get rid of the ugly old "moving axes" bit.

(+ reverted changes in unproject: need to be more careful since unproject
can be called outside Draw())

- added an option to force the size/position of the 3D grids/axes

- cleaned-up the whole size/position thing of 2D/3D grids: it's much
  more consistent now (and the GUI is nicer)

- rewrote the algorithm for automatic positionning of 2D graphs (now
  they rescale with the window, which is much nicer--and far more
  practical)

- the grid options now also apply to 3D views (this way we can
  finally get accurate size info for any data set; and the info
  is updated in real-time for gemeotry transformations & displacement
  maps)

- new option to specify the size of the moving axes

- generalized text align code (we now support the 9 modes that TeX
  does)

add option to specify the size of the small axes

- More intelligent way to detect if we need to apply a polygon offset
or not.

- better computation of translation coef in Draw2D

add color options for elements in views (requested by Philippe a long
time ago)

add all remaining colormap parameters as options

doc update

forgot to update help strings

fix typo

- 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

fix spelling

minor text mods

- fixed a couple of gcc warnings + added missing o->end() in
  jf's StructuralSolver plugin

- fixed the view option code: FLTK > 1.1.5rc1 breaks our use of
  widget->changed()...

- added background mesh support in the aniso algorithm

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

- added an option to draw the bounding boxes

- simplified the color_scheme options

- added tooltips to make the discovery of shortcuts easier

clip plane doc update

1.53 release

- generalized vertex array class to use reallocatable arrays

- introduced vertex arrays in post for all triangles: this speeds
  things up tremendously for ALL scalar views: 2d scalar views of
  course, but also for 3d isos (tets, hexas, etc.) and all smooth
  normals. The costly computations (compute the isos, get the normals)
  are only done ONCE each time the view is changed. Then we just pass
  the vertex array to OpenGL everytime we need to redraw (e.g. when we
  rotate the scene)

- removed the display list code alltogether: it's completely blown
  away by the new vertex array code!

for the record: with the new drawing code, you can

- rotate 500,000 triangles in real time on a 3-year old linux PC
(tested with a boing 747 surface mesh from CU: 10 times faster than
old code)

- display and rotate in real time 10 transparent+smooth shaded 3D isos
for a 1 million tet mesh (about 1 frame per second with the new code;
took tens of seconds with the old one)

Awesome :-)

update doc for vertex arrays

- removed context.default_plugin

- changed the main so that we load the plugins *before* we set the
  options (this way you can save your favourite plugin options in
  .gmsh-options, too)

- only save the options that differ from the default values (unless we
  explicitly ask to save everything)

- tweak the auto doc routines

- cleaned up the octree code (renamed some files, added copyright
  notices, indented everything)

- backported JF's doc from the texinfo file into the c++ code (the
  documentation is actually generated automatically by Gmsh with
  "gmsh -doc"!)

- replaced nPoints with nPointsU and nPointsV in CutGrid

- fixed a couple of printfs + removed some unused variables

use the 3d arrows by default

More "airplane" work...

- rewrote the way we handle lights: glEnable(GL_LIGHTING) is now used
  at the lowest level, where it belongs. This fixes many lighting
  glitches, and should make the whole stuff much more predictable;

- simplified the display modes for geometry and mesh: the choice
  between wireframe/solid is now independent of the choice of
  lighting/no lighting (and there is a new "Enable lighting" option
  for the geometry, too--even if it does only affect things like
  normals/tangents at the moment);

- brand new code to draw really nice (shaded) 3D arrows + 3 options
  that fully parameterize them (they can degenerate into pyramids,
  cones, w/ or w/o stems, etc.);

- new options so that we can also use the new arrows outside the
  post-processing module (e.g. for tangents/normals).

- "alt+d" now simply switches between solid and wireframe mode;

- new shortcut "alt+w" to switch the lighting mode for all the modules
  (geo/mesh + all post views) at once.

bring option docos up-to-date

better name for MacOS system menu bar option

Better doc for Show/Hide

Set View.ShowTime=2 to show the time value even if the view contains a single
time step..