[!112] add a plot function taking an 'on' parameter with values 'cells' and 'points'
Merge branch 'feature/addGeneralCellPlotting' into 'master'
See merge request staging/dune-python!112
(cherry picked from commit 06fd1478)
f3b205ca add a plot function taking an 'on' parameter with values 'cells' and 'points'