WINVER fixes for MinGW and VC++.
Fixed return value for WM_DROPFILES.
Fixed uncaught BadWindow in EWMH check.

Fixes #234.
Added multi-window support to events test.
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.