d3dx8 [patch 1/10] Implement D3DXPlaneFromPointNormal

Anyways, where should we put the d3dx9 code? I mean, we have 13 folders to choose from.. Perhaps It'd be better if we create a new dll (or at least directory) called d3dx9 were we implement all d3dx9 stuff and let the other d3dx9_xx dlls just call these functions? This would improve the clarity of the code structure, so that people that don't follow this discussion can also understand what we're doing ;-)