Special mission-only units

Since it looks like mission editor has returned to working state, I think I have some ideas for units which would be usable with it.

For a start, some “air control” units would be needed. Those are non-buildable units (they don’t even have to be visible) which have a special weapon, the only effect of which is that an air sortie is ordered to the point the weapon just hit (probably one type of sortie per unit). This will allow to order (properly functioning) enemy airstrikes from the editor without changing it or manually messing with lua (should make mission making simpler so hopefully more people can try it). AI can also use those to call in air for base defence vs player’s ground forces (if weapon range is limited) or interceptors (if the weapon is made to target air units).

This will immediately allow to make simple missions (of the “enemy waves” type) using greater unit variety than for ex. CRAIG can utilize.

We can also use the trains Yuri modeled on a fixed movement pattern.