Merge pull request #177 from fredericbonjour/Admin

Updated Backoffice.
Refactoring \Change\Documents\Query\Builder
Add \Change\Documents\Query\JSONDecoder
Merge pull request #178 from inthause/documents

Refactoring \Change\Documents\Query\Builder
Refactor \Change\Db\Query\ResultsConverter
Merge pull request #179 from inthause/documents

Refactor \Change\Db\Query\ResultsConverter
Add new Events 'documents.created' and 'documents.updated'

FIX Close db connection in some tests
Merge pull request #180 from inthause/documents

Add new Events 'documents.created' and 'documents.updated'
Enhanced main menu: style of close button, help and links at the bottom.
Added Change version in bottom of main menu.
Added <img rbs-storage-image=""/> directive. Value must be a valid "change://" file.
Added possibility to configure the template for previewing the documents in <document-list/>. Added new "thumbnail" attribute on <column/> elements for properties that store a "change://" image.
Refactoring.
Added thumbnails in Media/Image list.
Enhanced menu... :)
Fixed default route for Media module (points to Media/Image).
Added thumbnail columns in Catalog/Product list.