Update 0.71a

This is a fix for the homing missiles (yes, they work now I promise), and an attack/rank rules related change.

- The bug was very tricky and did not happen all the time, at least not for me. It could have been caused by potentially several issues it had, but the real problem lie in that the missile failed at disabling the sentry that spawned it as a collidable. This was further hidden by the fact that it instead tagged itself as uncollidable (with itself) and that it did not always collide with the spawning sentry either. Aaaanyway, it’s fixed.

- The rank/attack rule has changed so that a player cannot purposely sell all of his structures and thus lower his rank to a much lower level, attacking the farms there. This is implemented so that you cannot carry more money in cash than the target is worth. So, attacking a farm at rank 400 requires you to have less than 400.000 in cash, or the game won’t allow it. This limit is enforced when a player has more than 100.000 in cash, otherwise things are as before.

Also a few minor glitches were fixed, but I forget what.. Probably not very common cases I guess.