sql: join on SQL objects
WIP - clean join
table: add frequencies attribute to tableexprs
wip: clean sql join
replace frequencies with count_values
Test for API compat
Use reader method for into(DataFrame, CSV)
Merge pull request #645 from cpcloud/csv-date-logic

Parse datetimes in CSV.reader
Use the correct variable in mongo testing
Merge pull request #660 from mrocklin/frequencies

Add frequencies attribute to tableexprs
complex joins significantly cleaner
projection of join test
sql: lower_column test
sql: remove redundant projection code
sql: selections when predicate is a select
Merge branch 'master' into sql-join-clean
py26 fix with dict comprehension
Merge pull request #662 from mrocklin/sql-join-clean

Cleaner SQL joins
Discover for Series
Add tests for attributes