Migration to asset pipeline (part I)

I start migrating from the resources plugin to the more comfortable
asset pipeline.  I convert a lot of assets and GSP files where these
assets are used, but stopped at the document section because ElFinder
isn't availabe in a newer version.

Furthermore, I upgrade to jQuery 2.1.1 and jQueryUI 1.11.0.

At last, I change the DateTimeValueConverter class to parse ISO8601
date/time strings before trying to parse it using a localized format.