Nasty work round for NOT auto istalling calculator baseClass(s) as
plugins - revisit this and prolly turn baseclass in to real plugin skel
with flag to say not to include it
Add calc base class for constants -
prolly needs renaming and turning into a real base class later
wip - think asset rolluo to month level working ?
wip - asset level monthly agg seems to work I think
refactor zero of @readingsIn... to main _reset... funcs
Add asset / mac rollup for yearly
Fix date creation problem with just month and  year
Really fix the dates thsi time (month is zero based ...)
wip
add facility code (GTR etc.) to results records
wire up node-unit test harness
wire up node-unit test harness
wire up node-unit test harness