Merge pull request #1 from lyqyd/master

movehelp saveAction ordering fix
added getChunk() method

obviously getChunk will only work properly if the position, set manually
or from gps, has exact x and z values.
added getChunkPosition

getChunkPosition compliments getChunk. Where getChunk returns the chunk
coordinates of the current chunk, getChunkPosition returns the position
of the turtle within that chunk.
added reverse type slot iterator
fixes related to new reverse iteration,

drop calls reverse iterator for slots, so in most cases "overflow" will
be dropped instead of the "base" stack of samples. In many cases this
will prevent winding up with multiple partial stacks of items in the
inventory.
fix to issue #2

positive z is south, not north. :facepalm:
more fixes re: issue #2.

Wow, this whole snippit was full of fails. succ and forward(...) was not
even trying if previous step failed, had an x where I needed a z, and
was trying to move negative distances in half of cases, which is
basically a nop.
added proper reverse-order multi-slot support to refuel

like drop, refuel can iterate across multiple slots containing a named
item type, and does so in reverse order.
bug fixes & tweak to moveHelp

move now continues tracking moves when it is forced to dig with mode
"dig", and returns the set of moves as a 2nd return value.

Also fixed drop, which I'd partially broken in adding the feature of
dropping across multiple slots for named types.
added transferTo. Again.
changes made elsewise

REQ header