[sg] EW activation

We play that turning EW on doesn't take an action, but it can only be turned
on when the command squad is activated.

That means if the squad uses all three counters early in turn 1, it can't get
more counters until it is acivated in round 2.

In other words, you have to balance the use of your EW chits vs. the
flexibility of use of the command squad.

> The general drift was that the line "During it's