add seaplanes, add torpedo bombers, improve water and air unit behaviours

- build sonar before seeing an enemy shipyard
- fix bombers not prioritizing targets that explode big
- seperate torpedo bombers and bomber handling (but they share a counter)
- add torpedo bomber targetting
- fix erroneous sub mobility types in unittable, floating buildings will be shp
- resolve movestate issues: when attacking, battles roam, breakthroughs maneuver, and sieges hold position. when guarding or raidering, roam
- set units being repaired after resurrect to hold position
- replace units to ignore as attack target with checking its mtype (if it's not air)
- add seaplanes
- build torpedo bombers if there are submerged threats or underwater buildings (and don't build regular bombers if there are no ground threats)
- add land/water target detection layers
- don't scramble gunships for defense
- fix nil valuethreat bug in GetBestBombardCell
- get rid of looking for nanos for factory (turtles will suffice)