Fixed|Hexen: Extra artifacts given when jumping between hub maps

While the inventory is reset during map setup, a savegame is then
loaded, which restores inventory. The hub backup would then give
additional artifacts.

IssueID #1803
Fixed|FMOD: Crash when starting a song

One must take a copy of the provided sound font file name.

IssueID #1807
Fixed|Hexen|ACScript: Deferred ACScript task management

Due to a refactoring oversight, the deferred ACS task list was being
mismanaged when attempting to run the tasks when returning to a map
which had been visited previously.

IssueID #1804
FMOD: DMFmod_Music_SetSoundFont() mishandled null
Merge branch 'master' into defs-v2