Updated glsl code texelFetchBuffer -> texelFetch

This allows us to remove unnecessary directives
to require GL_EXT_gpu_shader4
Fixed some glsl preprocessor tests

Changed #if --> #ifdef for OSD_ENABLE_SCREENSPACE_TESSELLATION
Fixed glsl shader portability

- defined a fallback value for ROTATE
- made GetPatchLevel() a macro to avoid
  referencing gl_PrimitiveID from vertex shaders
- fixed float array initializers
Fixed glsl unsigned conversions in Gregory shaders
Fixed glsl shader portability (input,output)
Fixed glsl shader portability edgeDistance

Moved all edgeDistance declarations to client shader code.
Consolidated OpenGL includes into osd/opengl.h
Fixed VS2010 build warning/error