fixed bug with effectinfo.txt loading so that it now loads the proper

fixed bug with effectinfo.txt loading so that it now loads the proper
name for the map
added cl.worldmessage, cl.worldname, cl.worldbasename,
cl.worldnamenoextension strings (and sv. versions) as well as cvars

audited all use of these variables in the engine for consistent behavior
basename generation for maps now strips only maps/ prefix (allowing
subdirectory paths to be preserved)

git-svn-id: svn://svn.icculus.org/twilight/trunk/darkplaces@10185 d7cf8633-e32d-0410-b094-e92efae38249
::stable-branch::merge=ef9fefb7ab57b0bfe6c159b75ea905db519c7cdd