Make sure that shape strings are post-fixed with a null-char when read from file.

fixes #85
- adding Intel OpenCL kit in search paths

fixes #64
defining M_PI to fix some compiler errors on OSX 10.8

fixes #44
adding some ASCII art to document cryptic CV names in Gregory shader code.

fixes #86
Reading the cmake generator string to find out if it's a 32 or 64 build
and force DX SDK linking to detect the correct location.
fix CMake dependencies for shader string in mainApple.mm
fix missing includes

fixes #81
Fixed SRV format for level and valence buffers
Added DirectCompute backend for Osd Compute
Fixed default display modes in example viewers

Now the GL and DX11 viewers display surface+wire by default and display the correct keep-alive animation status.
Fixed a few build issues for OS X

Also, updated viewer_compat.cpp to more closely match viewer.cpp
Fixed a typo in the DirectCompute dispatch code.
Exposed DirectCompute by default in the DX11Viewer
Switching ptex coordinates structures to centroid based interpolation. This does not fix completely the problem though and we will have to revisit our guttering.

fixes #88
- fix broken ptex block allocation : iterates over all faces to find the longest edge
- code style fixes

fixes #89
Upload only the coarse vertex data from CPU to GPU
Updated to support GLES 2.0 on iOS and Android
Fixed build to switch on features not platforms

Also, allow updated to allow the default install path
to be overriden for Android NDK builds.
Added build instructions for iOS and Android
Fixed some typos in the top-level README
Fixed some more markdown typos.