Increase crafting distance to 6.
Merge remote-tracking branch 'dda/master' into increase-crafting-distance
Add map::accessable_items() to unify checking whether the player can access items at a given map location.
Use map::accessable_items() to prevent accessing items the player can't reach.
Restyle map::use_charges() and map::use_amount().
Eliminate extra indirection from within the map class.
Crafting distance improvement!