Adds parsing of effectiveTime[1] to medications

This is the schedule/frequency node, and allows us
to capture data necessary to display a medication schedule to users.

NOTE:
The implementation is very incomplete, only handles a subset
of the PIVL_TS cases. A real implementation would be MUCH
more complex.

Also, sorry about the whitespace changes. My editor removes all end of line whitespace on save. I can fix that if it's a problem.