Breaking changes

• Added RibbonControl feature (see my blog post Add ribbon tab to all site pages using Fluent Ribbon API for details)
• Added support for ToggleButton and DropDown controls
• Added RibbonController class, thus now user can add several ribbon tabs to a page.

Other improvements

• Added ControlsLibrary.StandardButtons class, so now user can copy appearance of his buttons from OOTB SharePoint buttons. See the FluentRibbon.chm file for more information.
• Added RibbonCustomAction.AddTabToContextualGroup method, which allows to add additional tab to some existing contextual group (for example, to the OOTB contextual tab group "List Tools")
• Added ability to change image size of inner controls of "container" controls, like SplitButton, FlyoutAnchor, etc.
• ImageLibrary.GetStandardImage now supports non-english environments (with overload)
• Added FluentRibbon.DelegateControl example project (can be found under Source Code tab)
• Added SPSite overloads for Provision and RemoveAllCustomizations methods of RibbonCustomAction class.

Bug fixes

• Fixed Small bug in RibbonCustomAction.cs, Creating EditForm/NewForm etc, only ribbon changes.
• Fixed an issue with CheckArrayHasElements validation rule
• Fixed 'Description attribute is not declared' issue with FlyoutAnchorDefinition
• Fixed bug with multiple TextBox controls