Cleanup.
* Fixed preview issue when using an external Collection that does not contain Documents.
* Added `local-sort` attribute on columns definition to operate a JavaScript sort on that column.
* Added button in header of date columns to toggle relative dates display.
[FIX] Some improvements in thumbnail generation
Removed console.log
Merge pull request #309 from franckstauffer/imagick

Some fixes on thumbnails
Add new document Rbs_Catalog_Attribute
Fix rbs-attribute-editor angular directive.
Merge pull request #310 from inthause/documents

Add new document Rbs_Catalog_Attribute
Added setting in user profile to define what to do when a Document is saved in an Editor ("back to list" or "stay on form").
Added directive on <time/> elements that allows display of relative dates.
Merge pull request #311 from fredericbonjour/Admin

Improvements in `<rbs-document-list/>`, User profile and dates display.
Added event to refresh the menu of an Editor. Used in the Attributes section of a Product, where the fields are dynamic.
Price module US translation
Merge pull request #312 from franckstauffer/i18n

Price module US translation
[UPDATE] Refactoring in User and Plugins with rbs-document-list
Merge branch 'master' of github.com:RBSChange/Change into user
Merge pull request #313 from renaudJennyRBS/user

Refactoring in User and Plugins with rbs-document-list
[UPDATE] add HTTP Status 500 in error cases of Plugins Actions
Fixed Models loading in Models service.
"selection" parameter is now optional on Actions declaration.