Adds a few tunes from Madness Combat as a standalone heist track in PD2.

Madness Combat 8 - Main Theme as stealth music
Madness Combat 5 - Main Theme as cover blown
Madness Combat 3 - Calliope as buildup (50% chance to play Madness 6 - API Madness instead)
Madness Combat 6 - Train Madness as assault music

Credits to Krinkels for making Madness Combat.

Changelog:
UPDATE 2 - Tweaked music volume
UPDATE 1 - Lowered stealth music volume and added Madness 6 - API Madness as assault buildup