* I assumed all obj/structure start as anchored
* I assumed wrong.
* I need to stop assuming things
* Anyway, bugfix for informal bugreport "throwing items at blankets causes them to get dislodged weirdly."
*Actually 2 types: one structure (unfolded), one weapon (carried)
*When in carried mode, has a verb to unfold and fill a up to 3x3 area
*Filling is blocked by Dense objects, except for tables.
*Tables follow a special logic: if center turf is a table, acceptable. Otherwise no
*However, if center turf is a table, we no longer accept tableless turfs
*If on table, we set layer just over table. Otherwise, we set it below all objs incl hiding ones
*Also adds a mapper variant that calls fold_out() on unfold() on init
*Mapper variant can be set to be unfoldable
*Creates codersprites for it all. It's "passable"