Add alien containment management to game

Accessible by right clicking alien containment in base view.  Invoked
automatically if alienContainmentLimitEnforced is enabled and
containment limit is exceeded after a mission.

Currently if you capture a valuable alien while going over containment limits then you are going to lose that alien.  This fixes the problem by allowing the player to boot out some useless soldier aliens to make some room for the navigator/leader/commander/whatever alien.

Management screen as seen via basescape, limits not exceeded
![screen021](https://f.cloud.github.com/assets/1824834/1309863/a84aa92a-31e6-11e3-9d83-74b36bd989c2.png)

Warning screen after a mission
![screen016](https://f.cloud.github.com/assets/1824834/1309845/546432f4-31e6-11e3-8341-4f76de6c57dc.png)

Management screen automatically invoked after a mission
![screen018](https://f.cloud.github.com/assets/1824834/1309910/5de9c252-31e7-11e3-8c8a-e8db63a72350.png)


After removing sufficient aliens
/65c6d560-31e6-11e3-8900-05dbe48452ac.png)

![screen019](https://f.cloud.github.com/assets/1824834/1309849/6b62a33c-31e6-11e3-87e0-8a7e16422688.png)

I confess I am still very clueless when it comes to palettes so a little tweak to this code is still necessary
![screen020](https://f.cloud.github.com/assets/1824834/1309850/6ff5b2ea-31e6-11e3-9e73-165b3106f103.png)