OpenGL2: Match glsl data type names: matrix_t -> mat4_t, vec*i_t -> ivec*_t
OpenGL2: Match glsl data type names: matrix_t -> mat4_t, vec*i_t -> ivec*_t
Merge branch 'HEAD' of https://github.com/ioquake/ioq3.git
#6059: OpenGL2: Read depths from resolve fbo when msaa is on in RB_TestFlare().
OpenGL2: Use RGBA16F format for HDR.

RGB16F is not 4-byte aligned and not supported by certain hardware.
End current draw surface before drawing cinematic

Fixes drawing StretchPic *before* CIN_DrawCinematic resulting
in cinematic being drawn before the StretchPic.
Fix signal 6 in S_Base_StartBackgroundTrack on OS X 10.9

In S_UpdateBackgroundTrack, s_backgroundLoop was passed to
S_Base_StartBackgroundTrack and tried to copy to itself using Q_strncpyz.
Make kamikaze timer loops use level.num_entities instead of MAX_GENTITIES

Optimization. Many other loops use level.num_entities, there was no
special reason that MAX_GENTITIES was used for these.
Update and rename README to README.md

adding analytics, I'm ready for DevHC to get upset.
Improve github interperation of README.md
Add header for standalone game licensing
Silence warnings about unused static functions in opengl2
Merge branch 'master' into sdl2
Readd backspace char event for UI VM text fields

UI VMs expect a backspace char event, but sdl2 branch only was only sending a key event.
Revert cl_keys.c to master branch (it would cause backspace to happen twice in console).