add into(DataFrame, pytables Table)
fix h5py/pytables import interactions
convert test to use pytest fixtures
use importorskip in fixture as idiom for skipping single test
Merge branch 'master' of github.com:ContinuumIO/blaze into into_pytables_df

Conflicts:
	blaze/api/tests/test_into.py
use consistent technique to skip tests based on import behavior
Merge pull request #455 from talumbau/into_pytables_df

add into(DataFrame, pytables Table)
Merge branch 'master' into compute-comprehensive
DataFrame -> pd.DataFrame in into.py
compute: only add mongo source if pymongo exists
try-except mongo imports