-Use ZDoom 1.23's sprite sorting comparison function, which will draw the taller sprite on top of the shorter sprite in when two sprites are at the same distance from the viewer. The previous comparison made such a case undefined, causing such sprites to flicker (See UDM3.WAD MAP31)

git-svn-id: http://odamex.net/svn/root/branches/rend32@3713 b0bcef46-2027-0410-bd56-ab726e9a1d04
-Fix horizontal wall texture alignment.

git-svn-id: http://odamex.net/svn/root/branches/rend32@3714 b0bcef46-2027-0410-bd56-ab726e9a1d04