Move __stdcall into the parens for function pointer definitions.

MSVC 2010 appears to require that it be located there.
Don't forget to install the wgl headers.

Fixes #26
Import registry from SVN 26622
Merge branch 'khronos-registry'
Bump version to 1.2 for release.
Adds support for OS X without X11.

OS X support shouldn't depend on X11 being installed on the host.
Removes the X11 dependency.