Updated extension headers.
Clarified comment on APIENTRY hack.
Added APIENTRY hack to native header.
Fixed fallthrough bug in glfwinfo.
Made context creation backends more consistent.
Added support for GL_KHR_context_flush_control.
Made clipboard string member name consistent.
Moved display closing into _glfwPlatformTerminate.
X11 library struct cleanup and comments.
Removed duplicate window position clearing.
Documented X11 cursor positioning caveat.

Closes #129.
Removed option to disable loading of winmm.
Window class cleanup.
Internal header cleanup.
Documented use of deprecated OS X function.
Clarified comments for X11 key repeat hack.
Added compatibility paragraphs on flush control.
Merged clipboard code into input.
wayland: Support for setting a cursor image

Closes #346.
Removed duplicate inclusion of client header.