Let people override index in dataframe constructor
Create a data frame per partition when loading from in memory collections
Add two simple tests for sorting
Re add the override of index support
reference some future work in the comments
Run the group by tests as part of the standard thing
Add two column groupby test
Implement groups() in distributed groupby
Add tests for ngroups and indices methods on groupby
Slight re-org, move more of the logic into groupby.py to allow us to optimize aggregations in the future
Add sum. it feels ugl
reduce some code reuse