v2.2.0

This release completes the transition of the included clinicaltrials.gov connector to use their V2 API. This includes two breaking changes in the private API for the ctgov connector.

1. In Connectors::Ctgov#load(start_date,end_date) the start and end dates must now be in ISO format YYYY-MM-DD (the old format was MM/DD/YYYY). Any custom tasks that directly call this method should be updated.
2. Connectors::Ctgov#load(start_date,end_date) now calls Connectors::Ctgov#process itself to recurse through the V2 API's paged results. Formerly, load and process had to be called separately in that order. Remove any direct calls to process in order to avoid a redundant re-processing of the last "page" of data from the API.