win32: add overlay to d3d9
win32: specify vertex declaration for overlay
win32: add opacity shader to overlay
win32: fix compile without HAVE_OVERLAY
win32: adjust makefile
style
win32: use color in d3d stock shader, pass valid color values
win32: use stock shader and color for overlay opacity
style
win32: style, remove left over opacity shader
Merge pull request #168 from OV2/d3d9-overlay

D3D9 overlay support