trivial
Rewrote ordered_2_combinations so that it would work on both legacy code and any dimension of NArray. The new method will always return an Array of NArray objects, where each of those NArray objects can then be passed to a new metric. This allows MM to accept metrics as an :intra_delta.

Also added a spaceship <=> method to create contour vectors.
Deleted all of the NArrayX hacks
Added some syntactical sweetener to make it easier to instantiate DistConfig objects from a hash. Now, you only need to pass in a symbol for @int_func, @mapper, and the deltas.
Added debug comments, made the mapping calls a little more friendly.
Made ordered_2_combinations return an NArray
revised the :narray_pairs mapper, revised the ordered_2_combinations and created a generalized method ordered_combinations
made :narray_pairs work properly as a mapper function
Merged changes from unstable into master
fixed mapper.
Edited self.vector_delta to work with narrays of any dimension, and generalized with a single call.
More changes to vector_delta so that the argument checking gives more useful errors. Also added comments to the spec header to specify the arguments' requirements.