Localize redactor

[mlocati]

To be able to localize Redactor with the current $this->requireAsset('redactor'); we need to update the redactor asset group.
So, in this pull request we have:

1. Some PRS-2 coding style fixes
2. Implemented assets de-registrations (when switching from a language to another one we have to reset the components of the redactor asset)
3. Added a new asset type: InlineJavascriptAsset. This is required since to activate a language we have to write a line of code like `$.Redactor.opts.lang = 'language code';``
4. Added (and normalized) the Redactor language files
5. Update the 'redactor' asset group when setting/switching a language

[Remo]

where did you get those js translations? There are two mistakes in the German translation file

align_center: 'Mitte',
center: 'Center'

should probably be:

align_center: 'Zentrieren',
center: 'Zentriert'

[mlocati]

where did you get those js translations?

From here: http://imperavi.com/redactor/docs/languages/

[mlocati]

There are two mistakes in the German translation file

Fixed 😉

[mlocati]

#419 is a simpler approach and can be integrated in Transifex (Redactor language files contains errors and are hard to maintain).