Add gamepad use to navigate into the model. Compiles on MS-Windows but still not works (to be done).

Major work on GUI : removed much-hated "menu window" & merged onelab tree in graphic window. Gmsh now requires FLTK 1.3.

(Additional changes: fixed crash when de-minimizing opengl window on mac os ; refactored Msg::StatusBar)

- fixed MED node ordering
- polished 64 bit Cocoa Mac OS X FLTK version
- updated copyright

Camera mode is avaiable with camera aperture tuning
stereo is available on stereo device only, otherwise the program
makes a segmentation fault with a openGL message :

"Insufficient GL support
 new gl windows for stereovision0x9477658
 Erreur de segmentation"

not work yet. Commented lines have been commit for CYAN/RED stereo but
this kind of stereo mode is not convincing.

utils/api_demos/mainGlut  :

- introduction of a class Camera to use function glulookat() instead of
rotation matrix in openGL viewport.

- A special implementation of the Trackball for stereo mode to be
consistent with other code (Abaqus, Catia, ...)

- adaptation of Drawcontext in Camera mode (works for mainGlut but to
  be validated in gmsh

with other toolkits than fltk

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)

- 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

drawing code from another widget toolkit)

- simplified background drawing (+added option to use jpeg/png image)
- better default clipping planes