Fixed the bug by replacing < with <=, as it wasn't checking chunks to
the right or below for items.  Should be working now.  There should actually
be a memory leak (valgrind isn't complaining, which is weird) because the
memory space allocated for items is never getting cleared.  Dungeons, overworlds,
and characters are going to need a custom deconstructor for when items get deleted.
Don't let me forget to do that.