add naive groupby function
Table By operation and python implementation
naive pandas By solution
better schema mismatch error
bigger pandas By test
bigger python by test
add reduction methods to Column
docstrings for table expressions
add count reduction to TableExprs
naive sql by operation
sql: multi-column group by test
python: simplify by
rename tpandas to pandas

Using __future__.absolute_imports fixes the naming issue
skip unary op doctest

Had py26 floating point issues
ensure that python layer works on iterators
add reduceby
by: test more complex apply
Merge pull request #263 from mrocklin/reduce-by

Tables Split-Apply-Combine