make negative physical entities behave like they're supposed to

removed the STEP parser: it's unusable, it makes the parser bigger,
and it introduces conflicts in the syntax.

- 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

- 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)

new plugins: Gradient, Curl and Divergence

- 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

- Replaced the general eigenvalue solver with a version from Laurent's
MatLib code (a bit more stable thanks to floating point checks with
adjustable tolerance)

- Added a solver for symmetric matrices (again from Laurent. Thanks, dude!)

- Added a small driver for 3x3 matrices, that selects the appropriate
solver (sym/nonsym) automatically

Don't call EigSort automatically in EigSolve, as it could screw up the
ordering of complex eigenvectors

make the EigSolve interface allow for the solution of eigenvalue problems
of arbitrary size (instead of limiting to 3x3)

complete JF's FindCubicRoots routine (complex roots)

- added Orientation() members for hexas, prisms and pyramids

- use det3x3() instead of ad-hoc code everywhere it makes sense

Fixed 3D cylinder/arrow drawing code when dir vector is // to z-axis

acos->myacos

Update copyright notice

Fix whitespace in copyright headers

Cleanup NR includes

This is a pretty big commit.

- The Numerical Recipes routines have been moved to their own
subdirectory: NR/

- These routines are now completely optional. Configure will
determine if they have to be compiled in (if it's a non-free version
of Gmsh) or if we should use the GSL routines instead.

- The GSL routines are there. Well, sort of. The SVD stuff works
great, but the minimization routines still need more work. The whole
infrastructure is there, though: we can already compile a fully GPL
compliant version of Gmsh by removing the NR subdirectory (or by
specifying --enable-gsl to configure).

- I also simplified the options passed to the compiler (OPTIM and
FLAGS).

That's all for today folks...

Updated copyright

which included commits to RCS files with non-trunk default branches.