Internalized ThingHitter to FSM

Resolved a few inconsistencies with this vs self, and added in missing
settings checks as well.
Removed unitsizet* and unitsized* in things.js

They now reference FullScreenMario.unitsize, so it'll be easier to
internalize the ObjectMaker.
Internalized class add/remove functions to FSM

addClass, removeClass, and the like are now part of FSM (since
PixelRender is internal).

Also messed around with this. verses no this. in FSM.
Added group switching and comments to GroupHoldr

GroupHolder.deleteObject, GroupHolder.deleteIndex,
GroupHolder.switchObjectGroup: equivalents of deleteThing, deleteThing,
and switchContainers.
Put characters, solids, etc. groups in window

This way they're unified with the FSM groups and easier to deal with.
Added applyAll and callAll to GroupHoldr

These act as similar functions to Function.apply and Function.call by
taking in a scope, function, and optional arguments, and applying that
function with that scope to each group, with the optional extra
arguments.