Added more special match rules for SP.

[NeonKnightOA]

Due to how the special field works, only one rule can be active at a time. Unlike the pre-existing rules, training and final, these won't modify the order of SP, just add a specific rule.

• instantGib enables IG mode.
• singleWeaponGA, singleWeaponMG, singleWeaponSG, singleWeaponGL, singleWeaponRL, singleWeaponLG, singleWeaponRG, singleWeaponPG, singleWeaponBFG, singleWeaponNG, singleWeaponCG and singleWeaponPL enable Weapon Arena mode with a specific weapon.
• grappleMatch enables the Grappling Hook.
• eliminationMode enables Elimination Mode with a SP-specific loadout.
• vampireMode enables Vampire mode, 50% of every damage dealt returns to the player in the form of health.
• lowGravity enables LowGrav.