Ignore past room bookings and events
TermTime and Booker room bookings and events starting before current time are excluded. If possible this is done by filtering the dates in the API call before filtering on timestamp itself.
Current time can be overridden in configuration file by adding a now
state value (ISO 8901 zulu format).
Added a couple of tests to get booker.py
to 100% in passing
May be easier to review commit at a time
Closes #31 (closed)