Fix for Mantis 3018: Setting a weapon's Target/HomingObject/HomingPosition etc doesn't work

git-svn-id: svn://svn.icculus.org/fs2open@10494 387891d4-d844-0410-90c0-e4c51a9137d3
From Axem & niffiwan: stop briefing/credits/mainhall music with scripting

git-svn-id: svn://svn.icculus.org/fs2open@10495 387891d4-d844-0410-90c0-e4c51a9137d3