change comm evo to timer_global

[rcorex]

changed commander evolution_condition to use timer_global (counts time from the start of the game) instead of timer (counts time from last evolution).

2 reasons:

• this works around the skipevolution bug
• this may be a better player experience for players to lose their commander early and rez them. they should get back the current level commander, but are still penalized with lower xp