gles2/tri: Add precision qualifier	to the fragment shader.

Port of Emil Velikov's mesademos change.
apps/gl: More comprehensive testing of glMapBuffer*
apps/gl: Use 3.2 core context to test MapBufferRange on Mac OS X.
cmake: Silence deprecated function warnings on MacOSX.
apps/gl: Test GL_EXT_debug_marker too.
apps/gl: Fix MSVC build.
apps/gl: Test fake viewport/scissor emission.
apps/egl: Stricter trace reference.
cmake: Avoid dependending on MinGW runtime DLLs.
Test texture object labels.
Test labels of framebuffer attachment.
Rename src json filenames to match reference more closely.
Allow comments in ref JSON again.
Update for thread ids formatting change.
Get cli tests to run in parallel without clobbering each other results.
cmake: Output a message when GLEW is found.
cmake: Don't force including windows.h

It causes problems.
cmake: Improve DirectX detection.

In respect to MSVC 2013 / WinSDK 8.1
apps/gl: Just require a recent GLEW.
Use a specific return code for skips.