Add SidebarCategories and Filters
Adding pretty cool icons to edit,create and so on..
Fixing toString bug
Fix edition of sidebar and other elements in the content dashboard

Conflicts:

	Controller/PageController.php
	Controller/SidebarController.php
	Controller/StaticContentController.php
	Controller/TemplateController.php
	Controller/WidgetController.php
Merge branch 'fix-dashboard'