hdf5: don't depend on fixed/strided dynd semantics
Merge branch 'master' of github.com:ContinuumIO/blaze
expr: binop propagates names when they're the same

Fixes #871
spark: make import robust to old versions of spark
compute: fix test due to binop naming change
spark: improve support for older versions
expr: datetime truncation name is same as child

Fixes #855
Merge pull request #872 from mrocklin/truncate-name

expr: datetime truncation name is same as child