The code setting metric names and units was moved from constructors to
an initialize method, to be called after translator initialization.
English Name is preserved as InternalName for metadata.xlm compatibility
in metric override.
Q_DECLARE_TR_FUNCTIONS(class-name) macro is used to set tr() context
when class-name is not QObject sub-class.
A few months ago I commented out the calculation of metrics
for manual ride files. This was a hack to avoid fixing the code
to handle metric calculations from overrides where there are no
data points.
This annoyingly meant that the 'rides' metric was zero for manual
ride files, and any derived metrics similarly were zero.
This patch fixes that.
All the existing wpk metrics concentrate
on the wpk for a fixed period, which is great
but we should also support it for an interval
(where it is arguably most interesting).
This patch fixes that.
Fixes#467.
