initialise default value for reveal control
synchronize reveal slider with standard slider
Reveal Controls: AllPlot

Added smooth slider and stack selection as the
reveal controls on the ride plot.
Initialisation of reveal controls
Fix thru today date selection on LTM

.. it needs to be applied every time a
date range is selected, so need a new bool
useToToday to flag that up.

Will need to fix the other date range charts
to do the same.
UseThruToday: Fix CP chart
UseThruToday: Fix Histogram chart
UseThruToday: Summary
UseThruToday: TreeMap