Ported the $On Action and $On Action Stopped scripting hooks from zookeeper branch. Also bumps the char limit for conditions from 32 to 64.

git-svn-id: svn://svn.icculus.org/fs2open@10254 387891d4-d844-0410-90c0-e4c51a9137d3
Improved the calculation for how many segments to use for drawing circles and arcs.

git-svn-id: svn://svn.icculus.org/fs2open@10255 387891d4-d844-0410-90c0-e4c51a9137d3