fix interactive mesh drawing + initial_only aniso

make "initial mesh only" option visible in scripts

draw interactive Delaunay in correct coordinate system

- fix discrete surf (for the 100000th time)
- new Status N command in parser to force mesh status
- create reverse discrete curves

workaround for Read_Mesh limitation when reading discrete closed
curves (missing last vertex due to List_Insert...)

fix crash + cleanup jf's msg

set char length from lines (useful if we want to mesh 2D from boundary repres)

cannot init iterator with 0: breaks on gcc 4.1

minimize the number of files that include GmshVersion.h: it's annoying to
recompiletoo many files just because the version string changes

new plugin to extract the geometry edges

moved most OS-dependent functions in OS.cpp

characteristic lenghts, that would lead to HUGE meshes (this is one
of the most common causes for erroneous bug reports on the mailing list)

ask confirmation to overwrite a mesh file when clicking on "Save Mesh"

remove obsolete BGM structure

removing dead code

better export mesh as post-pro view

polish

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

- better fallback when outside the octree
- disable bgm when optimizing in netgen

Rewrote the background mesh code to use the new post-pro octree instead
of the old brick stuff. It's 100x faster ;-)

make the bgmesh work with quads

fix Progression to actually do what we claim in the doc (missing -1 in
the formula: confusion between num_points and num_intervals)

fix bunch of gcc4 warnings

rewrote the smooth normal routines:

- the averaging is now done by clusters, which is much better for
  geometries that have sharp edges  (it's a little slower, but the
  visual results are much better)
- there is now only a single smooth normal container in the mesh
  (instead of one per surface)

add missing sanity check in interpolateUBS

- 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