Make Amiga music loop until fade out when changing scene. This is
based on watching a video of Future Wars Amiga walkthrough, not on
playing the Amiga version or reading its disassembly. But it does seem
that the music loops instead of just playing once.
Add support for dividing the playing rate of Paula and SoundFx audio
by integers other than 1. This is going to be used in the Cine engine
for dividing the playing rate of music in the Amiga version of Operation
Stealth by 2 to get it to sound right. Otherwise it sounds too high
pitched.
This is groundwork for fixing bug #11676.
The instrument names are a maximum of 22 characters in length but
were previously shortened to a maximum of 8 characters. At least in
Amiga versions of Operation Stealth some of the instrument names are
longer than 8 characters and failed to be loaded because of this.
Raising the limit from 8 to 22 characters fixes this.
Addresses bug #11676.
