* Declared I_SetSongPosition, I_GetSongPosition
* Implemented S_PositionMusic and S_GetPositionMusic
* Exposed in console TUNES and lua
* Implemented set position in SDL, SDL12, WIN32
* Implemented get position in WIN32
# Conflicts:
# src/nds/i_sound.c
# src/sdl12/mixer_sound.c
# src/sdl12/sdl_sound.c
# src/win32ce/win_snd.c