GitLab

* Added interactive debugging
* Better exception logging
* More tests for errors
* Added ONBUILD to dockerfile
  Now creating new images based on senpy's is as easy as:
  ```from senpy:<version>```. This will automatically mount the code to
  /senpy-plugins and install all dependencies
* Added /data as a VOLUME
* Added `--use-wheel` to pip install both on the image and in the
  auto-install function.
* Closes #9

Break compatibilitity:

* Removed ability to (de)activate plugins through the web