UI: Now the Unit Info screen has 'previous unit' and 'next unit' buttons
Ok, replace the buttons to more beautiful ones
Direct medics to the wounded body part

Currently the head is always selected when you open a medikit screen.
You then have to click on the wound if it's not the head.

This changes that by having the wounded body part already selected.
use byte 61 in MCD

it's the "xcom facility item" flag
add a 3-dimensional array for base modules

a 6x6 grid, 2 deep, containing info on how many destructible objects
were present at map beginning, and how many were/are left now.
won't break saved games.

AI will be attracted to non-defunct modules, and try to destroy them.
anyone destroying a critical component will lower the "current score" for
that module, when this hits 0, AI will pass it over.
destroy facilities after base missions

so if the aliens (or you) destroy a facility during a base defense mission,
that may have certain consequences, like cancelling a manufacturing project
or destroying a craft.
destroy disconnected facilities as well.

if a base module is destroyed in combat, it may break the connectivity
of other modules on the base. account for that shit.
remove unused "destructible" flag from ruleset
yay gravity fixes.
pixel fix for pathfinding thing
fix some broken walls in alien bases and abductors
fix sanity check
ammendments to facility destruct sequence
tidyin
fix typo

thanks to cfailde for pointing this out.
some explosion tweakage

don't start any explosions at a frame above 0, instead, range the starting
frame between 0 and -4 (meaning a 4 frame delay) and layer the explosions
accordingly. distribution should be more or less equal between these frame
delays.
Move path preview removal from inventory state to inventory button

because seems a neater place for it.
Fix inventory button in debug mode not always resetting TUs

Currently you need a unit with an inventory screen to reset TUs.  A lot
of aliens do not have an inventory screen so if there is no convenient
alien around you are stuck.
Fix displaying stats for wrong unit during debug turn.

Updates stats while watching aliens move; currently seeing stats
for the previous alien.
Also when you get to play aliens ensure that the stats for the
currently selected alien are shown; again previously moved alien
stats are displayed.
Fix broken string