Currently, the usgs parser finds the datetime for the most recent datapoint in medici and posts only data that was taken after that time.

Add functionality similar to the greon and umesc parsers - before a datapoint is posted to medici, all datapoints in medici are checked for the matching timestamp.

2014-12-10
Now the plan is to have the daily parser search for the most recent datapoint in medici and only add more recent datapoints, and add a second parser that runs, perhaps, monthly and validates/updates data (GLGVO-43).