Fixes half pixel alignment.
Uses the values reported by Darkstar2 on the forums, tested and can
confirm they work for me in all scenarios as well. WHen fullscreen
is fixed for Direct3D we should also ensure that pixel alignment
works in that system as well. Can be merged.
Merge pull request #735 from RobertBColton/master

I am pulling this with dissent. This is the most disgusting hack I've seen in a long time, but Microsoft does something similar (blaming it on OpenGL and pretending DX is unaffected) here: http://msdn.microsoft.com/en-us/library/windows/desktop/dd374282%28v=vs.85%29.aspx