Jonathan-David Schröder

Matplotlib support is now there with multiple images working: 

- [x] test in python console - [x] test in ipython console - [x] prevent wurlitzer macro non-enabling message on `import gmic` - [x] test in jupyter qtconsole - [x]...

Now works well without any command to write for UNIX users. See https://github.com/myselfhimself/gmic-py/issues/64#issuecomment-699175566

In Google Colab, after the 2.9.1-alpha1 release: 

In Jupyter Lab online: 

A pure ipython console, in a non-web setup, with DISPLAY environment variable unset, does not need to use wurlitzer to show console output, still there is a warning on G'MIC...

[Wurlitzer's code shows](https://github.com/minrk/wurlitzer/blob/2b923abb2b1156da0c009896ee1f077329ac1d9f/wurlitzer.py#L368) that when IPython has no kernel available, we are in within a terminal Python context, and wurlitzer itself is useless.

Good enough, will not be automatically tested, in order to give more time for other tasks

- [ ] fix non-displaying gmic.run("display",gmic_image_or_gmic_image_list) on Google Colab Related: https://colab.research.google.com/drive/1GNaAql2ZMwJ-8TL54jnpgnoHciCuIqtW?usp=sharing

Sticking to Stdc++11 g++ compilation under Linux. Libgmic gmic::run() now has more obvious default parameters possibly inherent to fresher stdc++ support than v11. Anyways sticking to stdc++11 by passing default...