New linedef execs: Trigger on Music Pos, Set Music Pos

[mazmazz]

Trigger on Music Pos

• Upper tex: Comma separated names to trigger on, wildcards included?
• Floor height: Pos to trigger on

Trigger on Music Name:

• Upper tex: Comma separated names to trigger on, wildcards included?
• Floor height: Pos to trigger on

Action: Set Music Pos

• Floor height: Pos to change to
• Can merge with Change Music?