Do not require a blz table to have columns of the same size
Adding script for doing an ooc groupby
First working implementation of an OOC groupby with BLZ
Get rid of the numpy import
Using set.intersection() as it is more elegant and efficient.
The table used for storing the groupby is persisted now
Make added columns persisted if the underlying table is persisted too
Merge pull request #80 from ContinuumIO/groupby

Out of core groupby example added