Replace deprecated GL api usage from gl_hud. It also supports OpenGLES.
more cleanup :
- consolidate cmake compile flags
- turn on -Wall
- suppress hidden overloaded function warning when using Clang
  (part of it is bug, part of it will require code refactoring
  on our end)
- add support for Maya 2013.5 for windows in cmake module
- clean up some glew includes which break builds with MSVC Express
  & Windows SDK
- move the bitmap for font_image into a compiled object
- remove some unused variables and other minor warnings

Note : this is a checkpoint, there are still a few more warnings to clean up...

fixes #96
Merge branch 'master' of github.com:PixarAnimationStudios/OpenSubdiv
Update README.md

Added -DNO_OMP flag description.
add the license banner to mayaViewer.cpp

fixes #96
Merge branch 'master' of github.com:PixarAnimationStudios/OpenSubdiv
fixing a int->float warning for MSVC
Merge branch 'master' of github.com:PixarAnimationStudios/OpenSubdiv
Fix OSD crash bug within CUDA & CL compute modules :

- remove the GL error check in cudaGLVertexBuffer :
  * unrelated GL errors left on the stack were triggering erroneous
  vertexBuffer allocation errors
  * we should not be checking for GL errors here anyway (as most other
  buffer allocations aren't checked either)

- add some pointer checking in the GL / D3D drawContexts in case the
  vertexBuffer pointers passed are NULL

- add some additional typedefs in OsdError to report some of the new
  CUDA / GL related errors
Remove deprecated GL calls, comply with 4.2/3.3 core profile. Use VAO, update glsl shaders, remove immediate draws, etc.
In example code, GLUT has been replaced with GLFW so that glViewer/ptexViewer can run on OSX (10.7 or later).

OSX note: still have some problem with clang, may need to explicitly specify gcc on cmake cmdline
 -DCMAKE_CXX_COMPILE=/usr/bin/g++

fixes #98
Fixed a buffer overrun error in OsdCLGLVertexBuffer::UpdateData.
Merge pull request #99 from njlitke/master

Fixed a buffer overrun error in OsdCLGLVertexBuffer::UpdateData.
bail out of Rebuild call if the VBO / VAO have not been allocated yet.

fixes #100
Merge branch 'master' of github.com:PixarAnimationStudios/OpenSubdiv
bail out of Rebuild call if the VBO / VAO have not been allocated yet.

fixes #100
change access permissions on files
exclude .inc.rule files generated by MSVC
- add cmake logic to parse package versions and include the correct headers
- add #ifdefs to work around the different versions of glfw
- add cmake logic to parse other packages versions and set minimum requirements
- fix X11 dependencies for static builds of glfw

- general Find.cmake cleanup

fixes #101
add glfw3 to windows section of glfw module

fixes #101
migrate osd_regression from GLUT to GLFW (this regression still needs work)

fixes #98