Merge Activity recalc derived series

.. e.g. so O2Hb and HHb are done for Moxy
ScatterWindow: Add Compare mode for 2D Plot
Spanish Translation Update
Ignored /release to keep git quiet on windows
Finally remove Old Ride list QTreeWidget !

.. its been there since the beginning at the heart of the code
   as a registry of the rides (RideItem) and controlling the
   selection of rides.

.. in v3.0 we stopped showing it, but it was still created and
   then hidden immediately. But removing the 'spine' of the code
   was seen as a step too far.

.. this is the first part of moving from SQL to a NoSQL cache
   for ride metrics, metadata and measures -- RideItem is now
   no longer inheriting from QTreeWidgetItem with all the issues
   that brings.

.. since its right at the heart there are likely to be unforeseen
   bugs as we go, especially since it affects the ride navigator.

.. add/delete has been tested a fair amount and should be reliable.
Save Command flushed Metadata first

.. to fix long standing bug with saving whilst editing
   a field. But still leaves a problem if exiting whilst
   editing a field (which is a bit weird tbh).
Add RideMetric::toString(bool useMetricUnits)

.. so we can now call that instead of doing the conversion
   and formatting all over the code !

NOTE: it still needs to be /called/ in the code, that change
      will need to be applied everywhere a metric is displayed
      to the user.
Added xPace metric
Computed as the constant pace on flat surface with the same LNP
Fixed copy and paste error
QVector::removeAt(int) is new

.. so use ::remove() instead for QT4 compatibility.
Remove Zones from RideItem

.. they are in Athlete::zones() et al now

.. this refactor was missed in the 3.0 mainwindow
   refactoring and is part of the prep to use RideItem
   as an in memory cache instead of the old metricDB
Fixup 3D plot for RideItem zones

.. missed in last commit.
Tidy up RideItem.h

.. the cache code can start now !
Added RideMetric::index()

.. each metric now has an index (identifier) that can is numeric
   starting at 0 and going up.

.. it can be used to offset into an array when we add a cache for
   storing precomputed metrics.
Remove unused local method 'unquote'
Fix virtual function to proper signature for QXmlAttributes reference and prevent hiding.
Turn off interval hover on leave

.. so you get hover notifications only when
   hovering, as soon as the mouse leaves the chart
   the hover goes away.
Introduce the RideCache

.. just a refactor of ridelist out of Athlete for now
   but will shortly be refreshing in background and
   loading and saving to rideDB.json
Added RideCache

.. source files missed off last commit
GC Upgrade

.. do not force User to scroll down to proceed
.. change "proceed" text to be more clear
Athlete Subdirs - improvements

.. added /BAK subdir where all actvities .BAK files are stored
.. do not delete any original files in /imports /downloads when deleting
activity
.. copy deleted activity .JSON as .BAK into /BAK subfolder
.. adjust upgrade procedure to copy .BAK files to /BAK