Nerf tank drones

By popular demand:
* Laser-locks for all turrets that use them (40mm frag, .50BMG, and 120mm HEAT) are now guaranteed to happen, rather than only being visible if you could see the tank (it can see you!)

* Laser locks for the 40mm and 120mm now time out quicker, making evasion a better option

* Tank drone's 120mm gunner AI only has 1 level each in marksmanship and launchers: it should be a pretty rotten shot now

* 120mm max engagement range decreased to 48 tiles from 50 (every bit helps)

* Friendly high-power turrets now use their full range, rather than (for whatever reason) being locked at 18 tiles max targeting range.  At that rate the tank would never use its 120mm on on your behalf, and both it and the chicken walkers would be awful stingy with their grenades.