In this part we have updated all the charts to reference
the RideItem::intervals() members instead of the TreeWidget
and RideFile::intervals().
The code to create/change/delete intervals is not included
so selecting and editing on charts/sidebar is disabled til
part 3 of the update, but hover should work properly.
Still left todo in future updates;
* Updates to the interval sidebar to list intervals
in a tree (by interval type) with a color selector
* Code to create, edit, delete etc the intervals via
the rideitem/intervalitem and see them reflected in
the ridefile
* Update to search for all the different types of
IntervalItems including routes and sustained intervals
.. and also tidy up use of isPeak() etc
.. starting to wonder if we need to a) auto find intervals on import
and then b) list them in a tree c) allow user to select a 'class'
of intervals to show (i.e. select all climbs)
