* remove all of the "from __future__" imports
* remove the first batch of rdkit.six imports/uses
* next step of rdkit.six removal
* removing xrange, range, and some maps
* next round of removals
* next round of cleanups
* fix inchi test
* last bits of "from rdkit.six" are gone
* and the last of the six stuff is gone
* strange importlib problem
* NP Likeness with confidence value
added a scoring variant with an additional confidence value between 0..1
that describes how many fragments of the tested compound were found in the model data set.
* fixed indentation
* added some documentation
* namedtuple, no rounding
* other changes to module as requested by reviewer
* replaced occurrences of sys.stderr.write by print
