Itom2dQwtPlot: AxisInterval properties return wrong values

[Valeriano Ferreras Paz]

Reading the "xAxisInterval" property of an Itom2dQwtPlot does not return the current values but the size of the plotted object -> [0, size_of_object]

Setting values works as expected.

Applies to xAxisInterval, yAxisInterval, zAxisInterval

[M. Gronle]

this issue is fixed in https://bitbucket.org/itom/designerplugins/commits/4d61a95b6e47e934ef8d3b8aa2f2427301c80609