Minor additions.

git-svn-id: http://pcsx2.googlecode.com/svn/trunk@5776 96395faa-99c1-11dd-bbfe-3dabce05a288
GSdx: 
Added a check box and config code for the fxaa shader. 
It's not currently hooked up since the shader setup might get replaced in a day or two.

git-svn-id: http://pcsx2.googlecode.com/svn/trunk@5777 96395faa-99c1-11dd-bbfe-3dabce05a288