Documentation work.
Added clearing of callbacks on window destruction.
Temporary fix for OPENGL_INCLUDE_DIR being NOTFOUND on OS X 10.8.
Merge branch 'master' into multi-monitor
Documented callback clearing at window destruction time.
Added saving of monitor mode count.
Formatting.
Removed legacy video mode generation.
Added OOM error reporting to X11 mode enumeration.
Moved internal API functions to correct section.
Moved NSGL context creation to proper module.
Merge branch 'master' of github.com:elmindreda/glfw
Removed return value of _glfwPlatformTerminate.
Removed glfwGetError and glfwErrorString.

The cached error code cannot be made per-thread unless it required
glfwInit (due to lack of __thread on OS X), which would be confusing and
partially defeats the purpose of it.

Beginners would use the generic error string facility instead of the
error callback and then be confused by its nondescript messages.

Storing the provided error code from within the error callback, whether
globally or per-thread, requires just a few lines of code and hands
control to the user without compromising thread safety.
Removed declarations of removed functions.
Added workaround for broken Mesa GLX_ARB_create_context_profile.
Merge branch 'master' into multi-monitor

Conflicts:
	src/cocoa_window.m
	src/init.c
	tests/iconify.c
	tests/reopen.c
Added explicit disabling of platform glext.h.
Ripped out horribly broken refresh rate mess.
Added generic video mode selection.