Gives Advent Captains the ability to call reinforcements to help them in the battlefield!
This ability can only be used once, and will only be used by the AI when he sees that you've wiped out all his buddies (is alone and facing multiple enemies). Hopefully this makes a previously underwhelming unit more dangerous, shifts player targetting priorities, and expands on a enemy unit concept that could have been so much more.

The ability uses one action point, allowing the captain make another move when called, or move to better cover before calling. The reinforcements are always on the alien team, and adapt to the players force level as usual (meaning harder enemies further into the game).

Feel free to give feedback, offer help on improvements, and scream at me if I accidentally broke your stuff.

*****Uses a UIScreenListener class - Apparently breaks the tutorial*****
*****Edits the Advent Captain Templates and their AI Behaviour tree*****

Changing the template can be temperamental. I've now made it so it adds the ability in the strategy screens, meaning a save loading directly into a battle *might* not have it - working on it.

ToDo:
- Figure out targeting methods/styles and use a more suitable one
- Figure out how to add Advent chatter to the animation
- Possibly get CineScript working for it
- Change the ability icon from evac to a custom one
- [strike]Possibly change the Ideal Spawn distance from XCom, based on feedback[/strike]

ChangeLog 19/02/16:
- Added .ini file to allow custimisation of the types of reinforcements called, and the distance it will try to call them to.
- Descriptive comments on how to change the reinforcements and create custom sets
- No longer spawns the in the center of the Xcom Squad, but a random direction, and your set amount of tiles, away.
- Default is 50 tiles away, but the game will always, no matter what you set the value too, spawn them within line of sight