-Clean up r_main.cpp, get rid of unused code.
-Remove basecolfunc, fuzzcolfunc, lucentcolfunc, transcolfunc, and tlatedlucentcolfunc.

git-svn-id: http://odamex.net/svn/root/branches/rend32@3907 b0bcef46-2027-0410-bd56-ab726e9a1d04
-Add a new client cvar r_flashhom, which fills the screen with a blinking blue color prior to rendering the scene. This makes HOM more visible for mappers. Note that r_flashhom is not saved to the configuration file on exit.

git-svn-id: http://odamex.net/svn/root/branches/rend32@3908 b0bcef46-2027-0410-bd56-ab726e9a1d04
-Floor and ceiling clipping should still be handled when a wall-tier's texture is missing.

git-svn-id: http://odamex.net/svn/root/branches/rend32@3909 b0bcef46-2027-0410-bd56-ab726e9a1d04
-Remove a couple of unnecessary tests from R_ClipLineToFrustum.

git-svn-id: http://odamex.net/svn/root/branches/rend32@3910 b0bcef46-2027-0410-bd56-ab726e9a1d04