WIP

Committing to get Kevin's test structure merged.
more WIP

Gagh, delays.
Still not yet ready.

Looks fearsome though!
Prototype

It compiles.  Gonna publish and ask for a second set of eyes on it,
though.
Merge branch 'master' of https://github.com/CleverRaven/Cataclysm-DDA into StrikeTheEarth
Merge branch 'master' of https://github.com/CleverRaven/Cataclysm-DDA into StrikeTheEarth
Best efforts

Kevin provided valuable insight into the coordinate and map code, so now
it doesn't wreck everything in a 48-tile radius or so.

Just now the bloody downstair refuses to happen.  Gagh.
ging oft a-gley

Compiles and doesn't mess up the ground, but also doesn't create the
upstair.  :-/
Remove unnecessary post_terrain

Turns out it's not needed.
Untangle gnarly coordinate mappings.
Merge branch 'StrikeTheEarth' of https://github.com/kevingranade/Cataclysm-DDA into kevingranade-StrikeTheEarth
Goin' Down!

Looks like it's working.  Might have been able to do it without Kevin's
help, but we're talking months if not a year at it.  So thanks for the
help, Kevin.  Much appreciated.

Now to either find a way to reduce rock_floor to "DIGGABLE" or check for
liquid in containers.
Remove testing-deduction

Almost left the debug feature in.  That's just too much fun.
make it 7 hours even

Still generous as compared to reality.
Merge pull request #6880 from KA101/kevingranade-StrikeTheEarth

A journey of 35,000 meters begins with a single swing