0.4.4

- [X] Multiple files packaging - CLOSE #163
  - [X] Move src/*.el files to /org-trello
  - [X] Add 'provide statements for each of those files
  - [X] Rework header + org-trello + footer files
  - [X] Adapt main org-trello.el files to reference the needed namespaces
  - [X] Adapt test files so that it continues to work (add the needed require statements)
  - [X] Adapt loading code routine for developing + testing
  - [X] Refactoring step - rename some files to avoid confusion
  - [X] Adapt README-dev.md to the current code adaptation
  - [X] Adapt cask packaging
  - [X] Add missing standard header to namespace
  - [X] Does org-trello still compiles? NO
  - [X] Fix simple compilation warnings
  - [X] Fix some more warnings
  - [X] Does org-trello's test work? YES
  - [X] Does org-trello work? NO
  - [X] Doc - Update docstring to standard emacs convention
  - [X] Fix org-trello to make it work again
  - [X] Test package melpa install (adapt org-trello recipe and test M-x package-install-file) - https://github.com/ardumont/melpa/blob/org-trello-with-multiple-files-packaging/recipes/org-trello
  - [X] Test package marmalade install
- [X] Update version
- [X] Release notes