v0.2.0

Diff since v0.1.5

• Support for Spark/Databricks.
• Change the translation API. Instead of generating SQL that updates the
  cohort table, translate a cohort definition into a FunSQL query that
  returns the cohort as a query output.
• Require FunSQL >= 0.14.

Merged pull requests:

• Updated for FunSQL 0.14 (#7) (@xitology)