Adds Mercenary's parry skill from Risk of Rain Returns. Multiplayer compatible.
Works like Risk of Rain Returns, go into a parry stance, if released right before an attack lands, you get a "perfect" parry that deals more damage, grants i-frames, and deletes projectiles around you. Damage is dealt in a 13m sphere (explosion) around Merc. There's also a 3m "graze" radius since the AI can be finnicky (graze projectiles do not damage you). There's also a "Fun Mode" in the config now.
