RideCacheModel Part 1 of 3

.. getting the model in and integrated with the
   ride list and diary

.. next steps to connect up to ridecache methods
   ::addRide and ::removeCurrentRide.

.. then fix up nits/bugs with diary view etc
RideCacheModel Part 2 of 3

.. add/remove ride now works

.. fixed metric value in data()

.. need to test (especially with the diary
   window and new athlete with zero rides and
   then import, add, delete, change, sort
   merge, split etc and push update to
   fix such bugs in Part 3