Cleaned up fix for #234.

XFree may not be passed NULL.  An invalid window handle will cause
_glfwGetWindowProperty to not return 1.
Desktop mode full screen fixes for tests.
Removed unused -s option.
Formatting (removed tab characters).
Fixed missing include in glfw3native.h for Cocoa.

Fixes #240.
Fixed meaningless Win32 video mode restore.
Cleaned up RandR video mode handling.
Removed background of <code> elements.
Updated version number on main page.
Removed C99-ism for the sake of OS X 10.6.

Fixes #241.
Added background colour for non-table and non-note <code> elements.
Removed <code> element background from other undesirable cases.
Added credit.
Fixed constness of function parameters.
Fixed refresh of debug context attribute.
Fixed documentation copypaste error.
Made GLX 1.3 the minimum supported version.
Made use of Win32 W-suffixed symbols explicit.
Further separation of window and context.

The context related parts of _GLFWwndconfig have been moved to
_GLFWctxconfig and given better names.  Window hint and attribute
members have been renamed to match.
Added missing link flags for threaded example.