1.0.0-beta.1

Added:

• Publish a master tagged docker image to DockerHub. It is supposed to reflect
  the master branch state.

Fixed:

• The simple_text_ckeditor plugin was not discovered as a python module and thus not distributed with Richie's python package.
• The organization logo maximal size is now restrained to its container size.
• We no longer publish development images to DockerHub as they appear useless.