Check availability of scans

[Hedede]

The bot should check whether comsats have enough energy to cast scans before sending units into lurkers.

See replay for 2018-04-13 17:09:57.

[Jabbo16]

Yeah this and improving the scans have been in my TODOs for a while, right now Ecg just scans when an invisible/cloaked unit is "visible" (not really) or has been burrowed for a second.
This currently wastes a lot of scans and also because of the lack of combat simulator for squad managing this usually results on a lot of suicides against cloaked units.

[Jabbo16]

Now the squads retreat when not scan energy available against cloaked units.