Update FTRK icon

Updated FTRK to use a new icon provided by @KatzSmile, located here: http://www.sleipnirstuff.com/forum/viewtopic.php?f=83&p=286374#286374. Matches the unit in game more closely as well.

Comparison of old (left) + new (right):
![flakicon](https://f.cloud.github.com/assets/566742/2330137/4b99ba9c-a42b-11e3-8a05-0a3dfb1676a9.png)