Check All Units are Dead Before Completion

[Vampurica]

Would like this done as a function call if possible to avoid needing to add a huge while loop to each mission.

No idea what it should look like though.

[mudzereli]

the ai cleanup code i wrote holds the units that are spawned for each mission, should be able to check both the distance of the player and the number of alive units in those arrays -- i can work on this