0.2.3

- [X] Version
- [X] Fix discrepancy between docstring and binding to delete the setup - https://github.com/ardumont/org-trello/issues/74
- [X] Use a prefix binding which does not override the emacs's default user prefix (keep the original for the moment to avoid disturbing people which already use it) - https://github.com/ardumont/org-trello/issues/72
- [X] Update documentation about the possibility to change the default prefix key
- [X] Fix ci-travis build due to change in cask installation command
- [X] Release notes