Fix pistol bug causing invisible pistols on mission start mostly exposed by mods that insert a new unit state before tactical setup is complete. Migrate effect team swapping code from X2Effect_MindControl to XComGameState_Unit to make it more widely applicable on any team change, not just mind control.
LW2 sets both of these flags, preventing impaired or burning units from triggering EV. Impaired and burning is also disabled via a pair of config flags, defaulting to off (vanilla behavior). Panicked units will no longer proc ever vigilant. Fix effects not ticking after a unit is mind controlled.
This fixes the case where a Grenadier had no grenades on loadout and therefore wasn't getting the LaunchGrenade ability when being AirDropped. Add an extra check to TempItem to look if the Unit has the ability attempting to be added.
