Simplified the output variable structure by removing the reporting frequency. That kind of fine control over individual output variables isn't used anymore; the full numeric table is either written or it isn't.  WIth this change, the LastDay event type is also obsoleted.
Removed some boilerplate code from the monitor modules by adding a function to create and queue a DeclarationOfOutputs event.
Removed several zone output variables as discussed in issue https://github.com/NAVADMC/SpreadModel/issues/209.
Merge branch 'master' of https://github.com/NAVADMC/SpreadModel
Zone monitor now recalculates area and perimeter only after days when 1 or more RequestForZoneFocus events has been seen.