Plot results with PyQtGraph

[aceglia]

Plot results using pyqtgraph instead of pyplot to add interactivity.

[pariterre]

I am strongly in favor of this! This was my first idea when creating the graphs, but at the time, PyQtGraph was not available on conda so it was hard to install. I am assigning this to you @aceglia We can work together when you are ready to swap the API!