CleverRaven/Cataclysm-DDA — pull request #3260 by NaturesWitness (2013-09-25 22:20:05+00:00)
Title: Make "variable size" stackable

In my quest to build a functional, 1-tile vehicle, I discovered you
can't install a wheel and an engine on the same square, because they
both have "VARIABLE SIZE" flags. I don't see why this flag shouldn't be
stackable, so I added it to the can_stack_vpart_flag list.