* moved the binding commands to osd.cpp. They were in the global namespace already and this way everything to be tossed out is in the same place when the time comes.
* removed support for the OSDs native CVARs. The only ones left were some internal ones I won't need until this code can be replaced.
* same for the custpmization code the games added. Duke Nukem was the only one anyway to have a decent font for it.
- consolidated the 3 identical S_OpenAudio implementations. The replacement code is disabled for the time being because it needs a rewrite. The replacement logic is uses is a bit too volatile.
- removed the old GRP scan code.
Note: enet uses 'malloc' and 'free' as field names in a struct - this does not work with any compiler using some sort of heap instrumentation that #defines these names!
This had to be changed to allow MSVC debug builds to compile again.