Set GL_TEXTURE_MAX_LEVEL and make mipmaps work!

git-svn-id: https://www.williamfeely.info/svn/dxgl@503 8a90861a-4eca-46d5-b744-240ff16d0c4d
Update DDraw caps.

git-svn-id: https://www.williamfeely.info/svn/dxgl@504 8a90861a-4eca-46d5-b744-240ff16d0c4d