boiler plate code no longer needed in store items
fixed crash on update from beta 6 to 7
fixed an issue with nested dicts
beta 7 WIP f

added a store item that upgrades the vanguard cannon
all guard gives 20 flak instead of 30
flak buffs increase counter-attack damage and -100 flak disables
counters entirely. closes #76
changed difficulty names and system. there are now 6 different options.
the Liberty's disable ability also causes the shutoff and flakdown
effect.
added 'right click to cancel' affect to a few more screens like orders
and preferences
beta 7 WIP g

tried fixing some compatibility problems. the 'can't find return label'
should be mostly fixed now (though you need a nightly version of renpy)
the 'can't find a place to stop rolling back ' is a much tougher nut to
crack and I haven't found a way to do it.

other than that, mostly just various bug fixes and minor improvments