Set pitch for texture upload and download.

git-svn-id: https://www.williamfeely.info/svn/dxgl@536 8a90861a-4eca-46d5-b744-240ff16d0c4d
Partially revert r536.
Define client buffer in glDirectDrawSurface.h

git-svn-id: https://www.williamfeely.info/svn/dxgl@537 8a90861a-4eca-46d5-b744-240ff16d0c4d
Revert pitch related changes from r536.

git-svn-id: https://www.williamfeely.info/svn/dxgl@538 8a90861a-4eca-46d5-b744-240ff16d0c4d