simplify TeX printing

Implemented new binary MSH file format (both read and write).

A 250Mb mesh file (6 million tetrahedra) is now read or written to disk in
less than 10 seconds (on my powerbook's slow hard drive).

added binary stl export

- SVG export
- more work on new geo database

typo

merging offscreen rendering from branch

- new button under the graphic window to temporarily disable mouse
  selection (speeds-up redrawing of very large models + permits to
  rotate/zoom-in a model in selection mode even when the whole screen
  is full of selectable entities--e.g. a surface mesh)

- new "lasso" selection mode (to select entities using the same kind
  of lasso as the lasso zoom: just Ctrl+click, then drag the mouse in
  selection mode; the shortcuts are the same as for the lasso zoom)

- it is now possible to unselect entities using the middle mouse button
  (only for the creation of physicals at the moment; not sure if it's
  useful in the other cases)

- new button in visibility browser to invert the current selection
  (very useful e.g. when multiple physical entities are associated
  with a given elementary entity, in order to "peel" away the model
  when adding new physicals; cf. philou)

- changed meaning of Escape shortcut (cancel lasso or toggle mouse
  selection) + restore standard fltk Escape handling for all dialog
  windows

- updated copyright string

- new mesh label mode (coordinates); all label types are now also
  available for mesh vertices

- added option in 'Print Option' dialog to disable printing of help
  strings

- added a comment string with the date when creating a new file

- new snapping grid for adding points in the GUI

Removed all compile-time depdencies on byte ordering (big- or little-
endianness). Replaced them with run-time conversions where necessary (only
for packing/unpacking of colors into unsigned ints). Performance hit
should be negligeable, but this will allow to compile Universal Binaries
on Mac in a single step (instead of having to compile the PPC/big-endian
and the i386/little-endian separately, which wouls be a royal pain in the
butt).

avoid repeated error msgs

print option dialogs now also show up when saving files "by extension"

cleanup+add comments so that students can understand what's going on with
the projection stuff.

(still need to cleanup the zooming in handle() to use gluUnproject() instead
of the ad-hock stuff that only works for an orthographic proj)

little hack to draw a gradient in the background. Nice for flashy
presentations ;-)

replaced ExportLCField with ExportMeshStatistics (lc + gamma, eta, rho + elem num)

removed all unnecessary glPushMatrix/glPopMatrix calls

Merged patch from Matt Gundry <mjgundry@faa-engineers.com> to support
the structured Plot3d mesh format.

- removed all the crappy STL code and rewrote it using JF's POLY_rep
  class

- generalized POLY_rep so that we can use the polygonal discretization
  as a surface mesh, and mesh in 3D afterwards. I.e., we can now take
  an input triangulation (a single surface in STL format, multiple
  surfaces in STL format, one or more surfaces defined using the new
  "Discrete Surface" commands), and generate a 3D mesh that uses it. We
  could in theory even mix triangulated and "normal" surfaces in the
  same geometry, but nothing is done at the moment to ensure that the
  mesh at the interfaces would match (if it does, it actually works
  very nicely)

- new STL mesh output format to export a surface mesh as a STL file

- added an option to the GEO output routine to save the surface mesh
  as discrete surfaces associated with the geometrical surfaces

- added STL and Text output formats for post-processing views (the
  text output allows for example to exploit plugin-generated data in
  gnuplot)

- generalized Plugin(Evaluate):

  * can loop automatically over all the timestep and/or components

  * can do operations using data from an external view

     - if the 2 views are based on the same grid, the plugin does the
       evaluation very efficiently

     - if the 2 views are based on differenet grids, the plugin
       automatically interpolates the external view data onto the
       grid of the current view

- added new Rand() function in MathEval

- default colormap is now # 2 (the Matlab "Jet" colormap)

copyright update

Added 2 options to control polygon offset. Instead of trying to guess
when a polygon offset is useful (it's no that simple when we combine
geo+mesh+some views), we just apply it conditionally to all surface
drawings.

generalized ExportLcField to all element types

- reworked the keyboard shortcuts with Laurent (our very own Macintosh
  Usability Guidelines Expert)

- new smoothing option for jpeg output

- new small GUI dialogs for ps/pdf/jpeg/gif/msh output (makes the
  'format' menu in the file dialog much shorter)

- removed the quads from the simplex trees (finally...)

  **warning**

  this is a pretty big patch that touches a lot of different files. I
  tried my best to update all the things that needed to be updated,
  but I probably forgot some things... Please test! (especially the
  export routines in obscure formats like SMS, Gref, etc., as well as
  the extrusion code)

- added second order edge vertices for hexas, prisms and pyramids
  (drawing not done yet)

- added sanity check for number of values in post-pro parsed file
  format

- merged all mesh printing/reading routines in Print_Mesh.cpp and
  Read_Mesh.cpp

- cleaned up the statistics code

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

- tweak the auto doc routines

upgrade gl2ps to 1.2.0

- add GUI for exporting characteristic length fields
- error->warning if lc <= 0
- don't enable POLYGON_OFFSET_FILL for 3D isos

Use bigger subdivision threshold for fake ps smooth shading