tweak getCanonicalRep - take in list of dictionaries (representing records) instead of data dictionary, take out data model set comparator to string distance for all fields
move canonicalize from api.py to convenience.py
update canonicalize in documentation
tweak canonicalization test
tweak getCanonicalRep so that it only takes one argument, a list of records in a dupe cluster
clean up conditional
documentation & docstring updates
style edits
Merge pull request #266 from datamade/canonical

Canonicalization API tweaks