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

avoid crashes if trying to transform a curve with no begin/end points

smaller init alloc in curves

Use the curve's end points id numbers for the end vertices (as we do
in the normal 1D algo). This is what the old extrusion algorithm
expects.

fixes for discrete curves/surfaces

copy/paste bug

modified Read_Mesh and Print_Geo so that we can save line/surface meshes
loaded from a file as discrete geometries

- New "Discrete Line" commands (similar to the Discrete Surface commands, but for
  curves).

  This permits e.g. to use Gmsh's extrusion mesh generators on 2D meshes (with
  boundaries) imported from other programs, and have all the useful elements
  generated (both volume and surface).

- Don't use Ctrl+m for File->Merge, as it is a reserved keyword for
  Window->Minimize on OS X:
  * File->Merge is now Shift+Ctrl+o (since it's in some way a variation of
    File->Open's Ctrl+o)
  * Tools->Options is now Shift+Ctrl+n

update less often for small meshes

Added progress message while reading .msh files (idea from Nicolas)

Instead of popping up a progress bar, I just used a Msg() call. Not
sure which is best, but this is a bit simpler..

make maximize reversible

add "Window" menu on Mac OS X

fix gcc warning

fixed crash when trying to extrude a discrete surface + minor mods in the faq

mention python

put call to value() after filter() so that we see the chosen file if we specify one

fix for the annoying "disappearing path" problem in the file chooser

simpler Start() function

removed extra white space and node coord format in UNV export

- added new "spectral" colormap (truncated hsv)
- added GUI button for elliptic mesh + geometry coherence
- added GMSH_MAJOR_VERSION, GMSH_MINOR_VERSION and GMSH_PATCH_VERSION
  in the parser

remove debug printf call

change orientations so that all the "discrete" sphere demos also work with netgen

add comments

don' draw full stem in filled mode

added check for socklen_t in configure script

fix normal orientation of second triangle

make simple arrows/pyramids look nicer when lighting is on

better estim of label width

allow negative line loop number in surface definitions

Adding python solver interface from Carl Osterwisch <osterwischc@asme.org>.

The interface comes with a example python "solver" that converts an Abacus
result file (in CSV format) into Gmsh post-processing views. Very cool ;-)
Thanks Carl!