stuff, like plugin drawing

Encapsulate toolkit-dependent global drawing functions in new
drawContextGlobal class, and add a static drawContextGlobal to
drawContext, with a default version that does nothing.

This allows to have a completely virtualized drawing system: we can
now ship a library with a fully working graphic system, indepedent of
the widget toolkit. A client code just needs to subclass
drawContextGlobal to get working graphics (see
e.g. api_demos/mainAntTweakBar.cpp)

re-committing work from last two days after server crash:

- refactored old Geo code (new/delete)
- moved DrawPlugin to Plugin
- move from matheval to mathex
- move from Flu_Tree_Browser to Fl_Tree
- fixed crash in Triangulate plugin

- moved GUI to FlGui + added experimental QGui to test Qt

- fixed most MSVC and gcc compiler warnings

- converted some remaining tabs to whitespace (that's why the patch is
  so large; please try to remember to indent with 2 spaces and not
  tabs when you commit stuff to CVS)

- merged modified patch from Konstantinos Poulios to allow saving
  physical/partition as element tags in mesh formats that don't
  support them natively

- replaced old 2nd order views with new adaptive stuff (still missing
  some function spaces for quads/hexas)

HAVE_XXX defines.

This fixes three longstanding problems:

- the API was hard to use because some headers had HAVE_XXX ifdefs, so
  that cient codes had to know how the lib was compiled to compile
  themselves

- we had to do make clean after each ./configure, which erased too
  much (e.g. most of contrib)

- make depend could include unwanted stuff since it redefined FLAGS

- fix bb computation to avoid model jumping around when adding points in z=0 plane
- pass interpol matrices as ref

There's no new functionality for now: PLEASE TEST THAT EVERYTHING
WORKS AS IT USED TO BEFORE.

multi-window & multi-coordinate system drawing.

There's no new functionality for now: PLEASE TEST THAT EVERYTHING
WORKS AS IT USED TO BEFORE.

ported Warp, SphericalRaise and Eigenvalues plugins to the new post-pro API

untabify

upgraded all plugins to work with the new post-pro.

This is done "cheaply" for now, by only using old-style list-based datasets.
Taking advantage of the abstraction (so that we can use the plugins on all
datasets) will require more work. The hooks for transparent data translation
are in place, but the actual translation has not been implemented yet.

moving to new post-processing database

                    *** WARNING ***

do not upgrade if you need plugins or adaptive views: these have not
been ported (yet) to the new database

                    *** WARNING ***

new gui for plugins (much better IMHO!)

- 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

add line elements in octree + little nicer Probe drawing

added interactive callbacks in CutParametric and Annotate

add element size computation

- generalized the octree code to make it work with all the element
types, and not only with triangles/tets (and fixed a couple of copy &
paste bugs in the process...)

- modified all depending plugins to take advantage of this

- generalized Plugin(CutGrid):
   * now works also for lines/points (i.e., when nPointsU and/or nPointV == 1)
   * new option ConnectPoints

- new Plugin(Eigenvalues)

- don't force color in Draw_PlaneInBoundingBox

copyright update

don't require gl2ps

missing line_width/point_size calls