Qwt support QT 5.4

.. we should think about removing our local version
   of QWT since we no longer need it.
Add ride resampling method

.. to convert from one recording interval to another
   when merging files.

.. this is a utility function that will be used by the
   merge rides wizard
JSON Strings and GC Tokens

.. fix json writing so that user metadata no longer conflicts
   with the tokens used by GoldenCheetah, e.g. a user entered
   "NM" in the workout code and that conflicted with the
   token used to delimit a torque value.

.. all user strings are now saved with a space " " appended to
   the value and when read, if there is a trailing space it is
   removed.
Updated Merge Tool Part 1 of 2

.. data can be sourced from file, download or list

.. next to update the mode (join or merge) and the
   merge strategy and parameters.

.. will also need to update the download dialog to
   allow you to specify which downloaded rides to
   process -- at present the merge tool assumes that
   the download dialog will only return 1 result

.. pleased with the way the download dialog is embedded
   within the wizard, will use that for other things!
RouteSegment: Add a new sidebar
IntervalView: Add a new intervals View
IntervalNavigator: Add new files
IntervalNavigator: Remove intervals from SubRide
IntervalNavigator: Add the interval
Make Intervals view optional till v3.2

.. we will develop over the next few months but it will
   not be ready for v3.11 so making it optional.
Gear Ratio SEGV Hack Fix

.. need to check if this hack fixes SEGV before raising
   with Joern.
Updated Merge Tool Part 2a of 2a/b

.. page flow and join sorted

.. committing before resolving the merging code
   - analyse() to identify offsets
   - combine() to merge into a working copy
   - ux for sliding offsets on a fullplot

.. next commit will complete this update to the
   merge tool

NOTE: MERGE IS NOT CURRENTLY WORKING SO PLEASE
      DO NOT USE IT !!!!
Updated Merge Tool Part 2b of 2abc

.. need to save away with analyse() and combine()
   now complete, and working pretty well on my data

.. now to work on the last piece, the 'adjust' page
   to shift data-series left and right manually (for
   cases where the calculated offsets are wrong or
   need to be tweaked by the user)
Fix Gear Ratio SEGV - addition to Hack Fix

... handle Gear Ratio as part of the existing logic - just without
smoothing
... solves SEGV problem in Compare Mode (and probably other areas of
AllPlot)