Fix traited Range (generator of floating point ranges)

When exploring the global coupling strength, the values coloured below the sliders give the impression that the parameter will be varied according to the interval [start, stop ]. However, when results come back, the parameter has been changed on the interval [start, stop)
This is evident in both PSE displays.

I guess the expected behaviour is the first one. This error is most likely coming from traits and the way the Range actually works.