Feature
validation-plugin: Introducing [validation plugin](http://www.aloha-editor.org/guides/plugin_validation.html)
Bugfix
metaview-plugin: We now disable the metaview once the editable is deactivated.
Bugfix
core: Some i18n strings within some modal dialog buttons were fixed.
Bugfix
core: Fixed Aloha‘s initialization order to ensure that repositorymanager will be initialized before plugins are initialized.