Use displayValue to format the datainspector label
DataInspector mode in TaurusPlot uses a hardcoded format for
displaying the Y value.
This causes issues when more precisionis required (see
https://github.com/taurus-org/taurus/issues/181 )
Fix it by delegating the formatting to displayValue()
(this requires
to have access to the associated trendset from the curve when
working on a TaurusTrend)
Fixes #181 (closed)
Known limitations:
The inspector does not react to changes in format while it is running (but new instances of the plot/trend will use the correct format)- The x value is not treated like the Y. This is a consequence of the X model being a "second-class citizen" (there is no TaurusBaseComponent associated to it and corespondingly no
displayValue()
method)