* Make make dir of output dir more consise and handle "  " case
* simplify verbose output

When multiple vtk files were given as arguments to the script together
with a base name for the output .csv files, a single csv file was
created that contained the data of the last given vtk file. This commit
adds an index to the file names in case multiple vtk files are provided.

[postprocessing] Add pvpython script to export 2d screenshots

See merge request !510

Do not offer possibility for user input

Christoph Grüninger authored 7 years ago and Thomas Fetzer committed 7 years ago

[postprocessing] Add colored help message indicating use of pvpython

See merge request !443

[bin/postprocessing] Add script to calculate l2error

See merge request !322

* Add possibility to choose variables also by name, instead of only by column

E.g for two plot-over-lines.