0.2.2

- [X] Version
- [X] Improve abstraction around data from trello (not complete yet)
- [X] Show people assigned to card - https://github.com/ardumont/org-trello/issues/67
  - [X] Compute user properties part from the board's informations
  - [X] Install board setup routine (C-c o I) also install board users
  - [X] Create board routine (C-c o i) should also install user boards (only the current user should then appear)
  - [X] Setuping properties before doing any actions
  - [X] Cleanup routine should also remove user global properties
  - [X] User assigns oneself to the card
  - [X] User unassigns oneself to the card
  - [X] sync-to-trello also assign users
  - [X] sync-to-trello also unassign users
  - [X] sync-from-trello also retrieve user informations and update the org buffer
  - [X] cleanup routine must cleanup card properties regarding user assigned
- [X] Update README about new command
- [X] Update README TOC
- [X] Release notes