-Remove all usage of the global ds_p in r_segs.cpp.
-Properly handle texture 0 with P_FindShortestTextureAround. Texture 0 or '-' usually implies no texture used on that wall tier but it should be used to indicate the height of the garbage texture AASTINKY.
-Texture::getHeight and getWidth no longer return a fixed-point value.
-R_DrawColumnRange now takes a function pointer parameter that accepts a drawcolumn_t parameter. No more R_BlastSolidSegColumn, etc.

git-svn-id: http://odamex.net/svn/root/branches/texmanager@4268 b0bcef46-2027-0410-bd56-ab726e9a1d04
-The server shouldn't allocate memory for a Texture's image data. It only needs to allocate the header portion of a Texture.

git-svn-id: http://odamex.net/svn/root/branches/texmanager@4269 b0bcef46-2027-0410-bd56-ab726e9a1d04
-Fix the vertical tiling of masked midtextures.

git-svn-id: http://odamex.net/svn/root/branches/texmanager@4270 b0bcef46-2027-0410-bd56-ab726e9a1d04