Update release notes for 13.05 release.

RELEASE_NOTES:
	Mercury now works on 64-bit Windows.

	Update email and web addresses for the project.

	The distribution is no longer split into three parts.

	Mention that we have a module for doing arithmetic on
	fixed-point numbers.

	Mention the GLFW binding.

	The Mercury team are no longer at the University of
	Melbourne.  (And the CSSE departement no longer exists
	by that name, anyway.)