Merge branch 'develop'
Release 0.3.0.
with_connection logs and raises error
refactor dataset columns into Dataset::Columns
Release 0.3.1.
extract Quandl::Cassandra::Models to separate gem
extract
extract cassandra_models
Release 1.0.0.
add quandl cassandra create, drop, reset, migrate, rollback
Merge branch 'master' into develop