Merge branch 'release/20140613-release' into develop

* release/20140613-release:
  bump version to 0.0.12
separate core from addons, to make conditional loading easier
remove unused jQuery.center
update redactor to version 9.2.5
restrict jquery-ui-rails version to be compatible with the sdk jquery-rails version
use latest jquery-ui-rails version again
allow multiple editors for a single cms field
added image drag & drop editor
first link editor version
allow to delete a link and update styling
add `data-autosave` to the string editor

fixes #19
update to ruby version 2.1.2

* cleanup gitignore
* add rake to development dependencies
update redactor to version 9.2.6
bump version to 0.0.13
Merge branch 'release/20140804-release'

* release/20140804-release:
  bump version to 0.0.13
  update redactor to version 9.2.6
  update to ruby version 2.1.2
  add `data-autosave` to the string editor
  allow to delete a link and update styling
  first link editor version
  added image drag & drop editor
  allow multiple editors for a single cms field
  use latest jquery-ui-rails version again
  restrict jquery-ui-rails version to be compatible with the sdk jquery-rails version
  update redactor to version 9.2.5
  remove unused jQuery.center
  separate core from addons, to make conditional loading easier