-Initialize ceilingclip[] and floorclip[] to negonearray and viewheightarray respectively. Column and visplane start/end heights are clipped to the screen contraints in BlastColumn.

git-svn-id: http://odamex.net/svn/root/branches/rend32@3879 b0bcef46-2027-0410-bd56-ab726e9a1d04