* separating geometry classes
* 2d geometry; retirement of the *3D suffix
* makings of an early block map datastructure
* entities in a zone - players, corpses, vehicles, deployables, ground clutter, and buildings - divided between sectors of the zone upon creation, management, or mounting; superfluous messages to keep track of blockmap state, for now
* trait for entities to be added to the blockmap; internal entity data keeps track of current blockmap sector information; calls to add/remove/update functions changed
* modified pieces of environment into an entities that can be added to a block map and have a countable bounding region; fixes for vehicle control seat occcupant collection; fix for squad individual callback references (original issue still remains?)
* introduced the block map into various existijng game calculationa where target selection can be reduced by its probing
* he_mines and jammer_mines now trigger if a valid target is detected at the initial point of deploy; they also trigger later, after a valid target has moved into the arming range of the mine
* conversion of interactions with zone into a queued, periodic set of tasks
* explosive deployable control -> mine deployable control
* tests repaired and all tests working
* mostly comments and documentation
* amenities are now represented on the blockmap
