Added more test scripts for matplotlib backend

Change-Id: I6922633674d2575e3670117f47cbff1e8ede4da6
Reviewed-on: https://iffwww.iff.kfa-juelich.de/review/36
Reviewed-by: Josef Heinen <j.heinen@fz-juelich.de>
Fixed 'NaN' bug for Matplotlib's draw_path routine

Change-Id: Ib15defe812a112200d91953db258a702b0548fc2
Reviewed-on: https://iffwww.iff.kfa-juelich.de/review/35
Reviewed-by: Josef Heinen <j.heinen@fz-juelich.de>