Fix MSVC build for far_tutorial_1
Fix MSVC build for far_tutorial_1 (linker error)

- typo in previous fix disabled the code instead of enabling...
WIP Far::PatchTables documentation
Extend export_obj.py Maya script to export uv set named 'map1'
Cosmetic updates to glFVarViewer

- apply image shader on background (look consistent with glViewer)
- fix retina display bug
Cosmetic update to glEvalLimit

- add image shader to fill background gradient
Cosmetic changes to glShareTopology

- add image shader to fill baground gradient
- fix retina display bug
Cosmetic update to glPaintTest code example

- added image shader to fill in background gradient
- fix retina display bug
Fix GL_DEPTH_TEST for GL code examples after adding image shader
Fix build warnings in sdc/bilinearScheme and sdc/catmarkScheme
Fixes the bug of glShareTopology. This example mutates patchDescriptor in drawcontext, so it needs a write access.
Adding another GetPatchArray() returning non-const reference. We should think about better API for this.
Fixes GL error caused by incomplete framebuffer on hud initialization.
Fix compiler warnings on 32-bit platforms.
Fix compiler errors for OpenGL-ES.
Fix linker settings for Android.
Added forward declarations for template specializations for raw topology data.
Add a first pass of optimization in CUDA kernels

Conflicts:
	opensubdiv/osd/cudaKernel.cu
Introduces a kernel for NUM_ELEMENTS=4. It's faster and not buggy,
anymore.
Fix Cuda compile warning in osd/cudaKernel.cu
WIP limit stencils factory

todo:
- fix rotated tangents on patches
- add "end-caps" (bilinear or Gregory ?)
- add pure bilinear stencil mode