First pass at an hbr regression test :
- generate baseline data with the new hbr_baseline tool
- run the a regression of the current hbr code over the baseline data-set with hbr_regression

There is still some cleanup to do to generalize some of the "shape" code as our intermediate
obj-like file format is unfortunately entrenching itself (we should really be using RIB...)

There is also a fair amounto f copy/pasted stuff in the regression code that needs to be refactored

Closes #32
Changed deprecated GLenum names
Change container get methods (HbrMesh::GetVertices, etc) to take
output iterators instead of std::vector - eases prman integration
for cases where std::list makes more sense.

Block allocate face children array in common case (<= 4 children).

Other, minor consistency edits.
HbrFace::Unrefine() needs to work with new face allocation strategy.
Merge branch 'master' of github.com:PixarAnimationStudios/OpenSubdiv
Oops - need osd regression to add proper libraries even if we don't really use them yet.

Closes #55
OsdMesh refactoring. Added OsdElementArrayBuffer and OsdPtexCoordinatesTextureBuffer, which manage GL resources on behalf of OsdMesh.
forgot to add new files. sorry!
(not so great) Fix for the hard-wired hbr regression path to work
with Windows.

Closes #58
Merge branch 'master' of github.com:PixarAnimationStudios/OpenSubdiv
fix crash bug of mayaViewer with edgeCreases
Added new maya plugin example which uses MPxShaderOverride to display osdmesh.
Fix FarVertexEditTables : include the correct hbr file and fix templating problems

Closes #62
Merge branch 'master' of github.com:PixarAnimationStudios/OpenSubdiv
Merge branch 'master' of https://github.com/PixarAnimationStudios/OpenSubdiv
Added OpenMayaUI lib
tiny comment fix
Fix sanity check for max value of level in FarMeshFactory::sumList()

Closes #73
Making CMakeList more consistent
Making CMakeLists more consistent