Renamed Anti-Tank to Rocketman. Added Cryomaniac unit (similar to Pyromaniac but deals freezing effect and ice blast.) Added Plasma and Electric weapon upgrade possibilities to the Marksman. Added Plasma weapon upgrade possibilities to the Assault and Heavy units. Made Assault and Rocketman and Grenadier able to attack aircraft. Implemented EMP Bomb, Ice Bomb and Plasma Bomb properly for the Grenadier. Added sounds to the Tesla Coil. Added weapon upgrade possibilities for the Attack Drone (Plasma and Electric). Merge branch 'master' of sbox-rts