0.5.2

Station.cs
- Added fields for viewing and following enemies
- Updated the update function to find the closest enemy if not following
- Updated the update function to follow an enemy if turned on, and
switch to a new one on followed enemy destruction
- Rotating the station stops following an enemy
- Clicking on an enemy sets it to be followed
- FindClosestEnemy() will find the enemy closest to a forward projection
vector stemming from the station
- LookAtEnemy() will rotate the station gradually to face the specified
enemy