added find_RL_coordinates_with_consecutive_hints, and
rigged differential_coords_finder to be able to use it, when given #2
and #3 inputs just integers!

Signed-off-by: Michael Donovan <mdono@math.mit.edu>
fixed differential_upgrader by removing a typo that was causing
it to refind coordinates unnecessarily EVERY TIME.
minor - made I2list and I3list always go in same order - was problem with
something being saved as a set.
Problem still persisted, as sort uses the memory address. Now it's fixed.
potentially sped up differential_upgrader by giving simpler hints
find_RL_coordinates_with_consecutive_hints was failing to return zero if
the element is off the map.
minor