[Issue 33] Support reading and writing parquet format via pyspark job.
[Issue 57, Issue 58] Amorphic API: Support Aurora Views and Materialized Redshift view.
[Issue 59] Support reading and writing json format via pyspark job and reading using pythonshell job.
[Issue 51] Dataset reload failed because _SUCCESS file was written before actual data. For now, user can pass reload_wait param in seconds which will wait before trigger reload.
[Issue 54] Amorphic API: Support new variables to dataset creation.