Simplified plotting call in during self.run()

Signed-off-by: Nicola Ferralis <feranick@hotmail.com>
Live Plotting now works correctly. Does not replot at each iteration.

Signed-off-by: Nicola Ferralis <feranick@hotmail.com>
Axis labels are preserved after restarting an acquisition run.

Closes issue #7.

Signed-off-by: Nicola Ferralis <feranick@hotmail.com>