Bugfix/demo fixes

[toth2peter]

Hi @hahnec

Two minor fixes in examples/04_illum_demo.ipynb:

• 'imagemagick' writer doesn't seem to be working, replaced to 'pillow' which is working well

• plenopticam dependency installation via !pip install plenopticam>=0.6.4 will not install version >=0.6.4 but will redirect the standard output of pip to a file =0.6.4. The package name and the version should be put between apostrophes.

Changes can be tested at https://colab.research.google.com/github/toth2peter/plenopticam/blob/bugfix/demo-fixes/examples/04_illum_demo.ipynb

Should you request any changes at this Pull Request please contact me, thanks in advance.

[hahnec]

Hey @toth2peter.

Thanks for the PR and pointing this out. I will merge your findings for the upcoming release as I am occasionally working on a v0.7.0 of plenopticam.

'imagemagick' was actually only supposed to run on my local machine as it proved to render gif-animations with a more pleasing quality than 'pillow'. I might add a try-except block later for a safer export. Thanks for fixing the versioning in the Colab notebook.