Automex user feedback

[sprunk]

Reasonable-sounding requests from players.

1. make it so that area-mexing constructors automatically reclaim enemy mex nanoframes.
2. make area-mex terraform the terrain if a mex spot is unbuildable.
3. make constructors on Attack-Move (Fight) capture mexes.

[sprunk]

My reservations:

• 1 sounds alright but annoying to implement since right now area mex is just a bunch of fire-and-forget native engine build orders.
• 2 allows units to be stupid. Now they have to choose an optimal terraforming type, and not get baited into wasting unreasonable amounts of effort/resources on particularly bad spots, including ones where enemy is present or even also terraforming in the opposite direction. Also involves a bit of point 1, where the order is one-time while terrain can be discovered to be bad only after the order is given. In practice most spots unbuildable due to terrain are easy cases like a janus hit in the sand though.
• 3 sounds annoying for combat cons (shieldcons in a shieldball, welders), for bait mexes (adamantine mountian), maybe for commander (and if he's not covered that somewhat hurts discoverability of the feature). But maybe that would be a toggleable tactical AI.