Jupyter-manim

Feature/bugfix: imports from the current evironment are now included in the manim script 11

Added support for gif output (`--save_as_gif` or `-i` options)

Fix two Windows-specific issues were fixed:
- always close the pickle file
- provide the file paths as a raw string to avoide escape issues

- Export of variables from the notebook into the manim script using pickle
- Base 64 encoding option

- fixed permission error issue on Windows OS 1
- use of `--help` and `-h` flags does not result in a warning about no path to the output animaton