[AD] 5.1 D3D hardware blending doesn't work

[John-Kim Murphy <leftium@xxxxxxxxxx>]

- Textures in ex_draw_bitmap don't look right:

• Texture mode looks visibly different than memory buffer mode.
• Alpha Blending
• [texture] areas outside circles transparent, but inner regions not translucent. 
• [memory] inner regions translucent, however entire window gets noticeably darker.
• Additive blending
• [texture] looks like what I'd expect alpha blending to look like? Sprites are not nearly as dark as usual.
• [memory] looks OK.
• Tinted blending
• [texture] no red tint at all.
• [memory] looks OK.
• Solid blending
• Both modes look OK

- ex_haiku doesn't look right, either. (background light color doesn't change with elements)

- ex_blend actually looks OK, except the font shadows are rendered as white

- ex_blend2 actually looks OK as wel, except the black fonts are rendered as white

Environment: Allegro 5.1 r14300. MSVC Express 2010 + Windows 7, DirectX SDK June 2010.

I'm pretty sure the D3D driver is being used.

John