Merge branch 'master' of github.com:ContinuumIO/blaze
into: list <- numpy - better datetime handling

Nanosecond datetimes converted to datetime objects, not Longs
into: DataFrame <- CSV support datetimes with parse_dates
into: exhaustive test - add datetime support
into: exhaustive test with basic compute
into: exhaustive test - refactor data sources
into exhaustive: remove csv from base targets
mongo: tests skip if no mongo server running
python 3 compatibility
into: exclude into(nd.array, *) test with datetimes
Merge pull request #497 from mrocklin/into-persistent-test

Continue to test and improve `into`