Merge branch 'release/v2_1_0' into dev
Fixed invalid initialization of glslTransformFeedback kernel.
Fixing search path suffixes for ICC libs
Fix cpuEvalLimitController crash bug

Properly check that derivative data is bound before passing pointers to the kernels.

fixes #218
Adding null checks
Adding support for subdivision stencils.

- Adding FarStencilTables and FarStencilTablesFactory classes
- Adding Osd EvalStencil context & controllers for CPU, OMP and TBB backends
- Adding the code example glStencilViewer
- Adding reST documentation
- Changing version to 2.2.0_dev
- Fix HbrMesh::Unrefine function
- Fix "CanEval" function in OsdVertexBufferDescriptor

Note 0: there is no stencil support for hierarchical edits

Note 1: there is no support for face-varying data stencils yet

Note 2: the current stencil factory is lazy but the caching system is not re-entrant
Fix osd_regression build

osd_regression needs to link against all the appropriate OSD dependencies, including possibly CUDA, TBB, ICC...
Release 2.2.0
Merge branch 'release/v2_2_0'