C++ and style cleanup only

Minus voids, reverting ++ styles, alignment.
Allow zero-size textures (must force to be 1x1)
Bug fix for MAPINFO music

Whether to apply a prefix to the lump name depends ONLY on whether or
not the lump name is prefixed.
osx:
* Updated xcode project
* Added missing (but required) prefix header, which ought to be needed by the one obj-c file in EE
Fix PSX spectre translucency level
C++ style and typo fixes only
Add Arch distro BFG Edition to search path

chungy says it is kept in /usr/share/games/doom3bfg
Use opendir to find nerve.wad

Resolves issues with system filename case sensitivity by using the name
as it appears in the directory listing.
Remove unneeded qstring construction
Merge from Master
Made PortalClipEngine extend DoomClipEngine. (Slight change of strategy)

I realized that the PortalClipEngine::slideMove would look pretty much
the same as DoomClipEngine::slideMove, same with the teleport move
functions, so I made PortalClipEngine extend DoomClipEngine and then
removed those method overrides. Seems to work just fine :) Doing this
will allow me to concentrate on the clipping code a feature at a time
rather than having a big broken thing that has to all be re-written.