Move S_DefineSound, S_DefineMusic, and S_DefineAudioIfSupported out of...

Move S_DefineSound, S_DefineMusic, and S_DefineAudioIfSupported out of game.cpp and into sounds.cpp, and made CON_DEFINESOUND use S_DefineSound, reducing code duplication.

requested review from @terminx

This conflicts with some changes I've been working on in a local branch here, but I am in favor of including these changes once said branch is ready to be merged into master.

Sounds good to me.

added 10 commits

• 4374a63b...2d6473e4 - 9 commits from branch terminx:master
• c38987bb - Move S_DefineSound, S_DefineMusic, and S_DefineAudioIfSupported out of...

Compare with previous version

merged