added python_join from data tools
tidied up python join syntax
small formating improvements
added print method
more tidying up
started integrating python join
fixed syntax error
refined python_join
renamed python_join to join
started adding group by
group by functionality now working
made group by more future proof - easier to write more aggregation methods
minor format
added avg method to group_by
added some docs, and formated group_by
Made the variables dim_modules, dim_classes and dim_map class variables instead of being static variables
reverted formating
some refactoring, and pylytics wasn't passing in right_join
added support for keeping arbitrary columns from joined query
Merge branch 'debug_update_all' into python_join