Draw contexts do not fully initialize patch arrays #281

* added the numVertexElements argument to Osd*DrawContext::Create, which is used to initialize the patch arrays when calling OsdDrawContext::ConvertPatchArrays
* removed the unused level argument from Osd*DrawContext::_initialize
* maintenance work on CL/D3D11 bindings to get them to compile
Changed FindGLFW.cmake so that setting the %GLFW_LOCATION% environment variable in Windows behaves like the CMake option, "-DGLFW_LOCATION=%GLFW_LOCATION%".
Fix a bug of OsdUtilMeshBatch, the varying buffer isn't computed with CL kernel.
Merge pull request #282 from nathan-at-digitalfish/issue281

Draw contexts do not fully initialize patch arrays #281
Merge pull request #283 from nathan-at-digitalfish/fix_find_glfw

Change to FindGLFW.cmake for Windows
Compile osdutil with -fPIC for correct linking in Presto.
Added an option to FarMeshFactory to generate triangle patches instead of quadrilateral patches for a uniformly subdivided mesh.  This option is applicable to GL-ES, which does not support quadrilateral primitives.
Added a public constructor to OsdMesh that initializes the members objects from its arguments, allowing those members to be created by a subclass or an external function.

* maintainance work on the D3D11 specialization of OsdMesh to bring it in line with the other template specializations
* updated the facePartition example to derive PartitionedMesh from OsdMesh in order to allow other vertex buffer and compute controller configurations
Add correct OpenSubdiv namespace begin/end blocks.
Update release notes for release 2.4.1
Release 2.4.1
Merge branch 'release/v2_4_1' into dev
Merge pull request #285 from nathan-at-digitalfish/add_osd_mesh_ctor

Add a public constructor to OsdMesh
Add missing third parameter to templated OsdDrawContext usage, caught in Presto build.
Merge pull request #280 from Nazg-Gul/dev

Return success status from openSubdiv_finishEvaluatorDescr()
Changes to address comments in #284.

* rolled getNumFVarVertices into allocateTables
* renamed tessellate to triangulateQuads (technically speaking, Loop scheme uses a trivial triangulation)
* condensed the pointer arithmetic used for triangulating the data tables
Merge pull request #284 from nathan-at-digitalfish/add_far_triangulate

Generate triangle patches for a uniformly subdivided mesh
Fix Windows build warning in FarPatchTablesFactory
Fixes a bug introduced in 808aabf that causes OsdUtilPatchPartitioner to fail to rebuild the face-varying data table correctly for triangle patches.
Merge pull request #289 from nathan-at-digitalfish/fix_fvar_triangulation

OsdUtilPatchPartitioner failure for triangle patches