[dx9-16] Basetexture support

[Robert Shearman]

Ann and Jason Edmeades wrote:

>This patch adds a parent class to the various types of textures 
>
>Changelog
>
>Add BaseTexture class support, call from d3d9.
>
>Jason
>
>Note: This adds a new file, basetexture.c which is also part of the patch
>  
>

The ref-counting in this patch looks a bit suspicious. Does 
This->resource.parent point to an object that holds a ref-count on the 
IWineD3DBaseTextureImpl object? If so, then that would lead to a 
circular ref-count where neither object would be freed.

Rob