Finished off the GLSL compiler's support for parsing shaders using OES_EGL_image_external.

The GLSL to HLSL translator work is not done yet so the extension is disabled in Shader.cpp.
Review URL: https://codereview.appspot.com/5530081

git-svn-id: https://angleproject.googlecode.com/svn/trunk@946 736b8ea6-26fd-11df-bfd4-992fa37f6226
7 files changed