Minor changes to fix typographical errors, and for consistency across class method prototypes.
Added the CATMARK_QUAD_FACE_VERTEX and CATMARK_TRI_QUAD_FACE_VERTEX kernels.

* The CATMARK_QUAD_FACE_VERTEX kernel calculates the face-vertex for a quadrilateral face.  It applies to every face after the first subdivision step, and may be applied for the first subdivision step of a quadrilateral coarse mesh.

* The CATMARK_TRI_QUAD_FACE_VERTEX kernel calculates the face-vertex for a triangle or quadrilateral face.  It may be applied for the first subdivision step of a coarse mesh composed of triangles and/or quadrilaterals.

* Both kernels calculate each face-vertex using four vertex indices (triangles are specified by repeating the third index).  Therefore neither kernel uses the F_ITa codex table, and instead the first vertex offset in the F_IT index table is stored in the FarKernelBatch's table offset.
Merge branch 'release/v2_5_0' into dev
Implemented CATMARK_QUAD_FACE_VERTEX and CATMARK_TRI_QUAD_FACE_VERTEX kernels for CUDA, GLSL Transform Feedback, and GLSL Compute platforms.
Implemented CATMARK_QUAD_FACE_VERTEX and CATMARK_TRI_QUAD_FACE_VERTEX kernels for DirectX 11, OpenMP, and TBB platforms.  Fixed a bug in the GLSL Transform Feedback kernels.  Minor changes for consistent formatting.
Fixed a compiler error in the GLSL Transform Feedback kernels on OS X/Mavericks.
Merge pull request #308 from nathan-at-digitalfish/new_face_vertex_kernels

New face vertex kernels
Fixed mesh batching for the CATMARK_QUAD_FACE_VERTEX and CATMARK_TRI_QUAD_FACE_VERTEX kernels.
Merge pull request #309 from nathan-at-digitalfish/fix_mesh_batching

Fix mesh batching
Fixed an error in the DirectCompute shader.  This resolves https://github.com/PixarAnimationStudios/OpenSubdiv/issues/313.
Merge pull request #318 from nathan-at-digitalfish/fix_direct_compute

Fix for DirectCompute tri-quad face-vertex kernel
Fixes to boundary interpolation in osdutil.
Fix bilinear stencil tangent computions

- fix a couple of sneaky typos in the FarstencilTablesFactory

fixes #319
Update release notes for release 2.5.1
Release 2.5.1
Merge branch 'release/v2_5_1'