-Add two-dimensional vector types for each of the fixed-point precision types.

git-svn-id: http://odamex.net/svn/root/branches/texmanager@4365 b0bcef46-2027-0410-bd56-ab726e9a1d04
-Remove the use of the patch_t struct in TextureManager when loading lumps and use lump offsets to get the patch dimensions instead.

git-svn-id: http://odamex.net/svn/root/branches/texmanager@4366 b0bcef46-2027-0410-bd56-ab726e9a1d04
-Forgot to convert from little-endian to native byte ordering when reading a patch's column offset, probably leading to crashes when reading patches.

git-svn-id: http://odamex.net/svn/root/branches/texmanager@4367 b0bcef46-2027-0410-bd56-ab726e9a1d04
-Remove usage of post_t by TextureManager and instead use offsets to access topdelta and length fields of a post. This makes the code a bit more readable as it removes a lot of casts to and from post_t pointers.

git-svn-id: http://odamex.net/svn/root/branches/texmanager@4368 b0bcef46-2027-0410-bd56-ab726e9a1d04