Added DirectInput joystick code, contributed by Glenn Maynard.

This fixes a problem with the Windows Multimedia joystick driver
not showing all 6 axes on a GameCube controller converter, which
was donated by Jacob Kolding.

--HG--
extra : convert_revision : svn%3Ac70aab31-4412-0410-b14c-859654838e24/trunk%401820