Upgrade spring-faces to JSF 2 as a minimum requirement

* Rework all state handling, removed FlowSerializedView class and save
state as opaque object
* Use FacesWrapper classes instead of custom delegates
* Deprecate isAtLeastJSFXXX() methods and removed all internal use
* Remove all Jsf2XXX versions of classes
* Refactor all calls to deprecated JSF methods
* Removed older VariableResolver and PropertyResolver classes
* Deprecate Jsf2FlowResourceResolver and log warning if used
* Create new FlowELResolver to replace removed VariableResolvers and
PropertyResolvers
* Update faces-config.xml to use newer xsd
* Significantly rework FlowFacesContext to remove the message delegate
and generally improve the code
* Added "provided" dependency to MyFaces and fixed partial state saving
on MyFaces
* Fixed FlowResourceResolver to delegate to both MyFaces or Mojarra
depending on availability
* Add JsfUtils.findFactory method and rework existing code to replace
FactoryFinder calls and casts
* Refactor JsfViewFactory to improve code readability
* Rename FlowViewStateManager and FlowViewResponseStateManager to
FlowStateManager and FlowResponseStateManager
* Ensure ResponseContextHolder is reset after each test
* Update JSF portlet support to function with JSF 2.0

Issue: SWF-1536, SWF-1540, SWF-1550

src/dist/changelog.txt

@@ -5,6 +5,8 @@ http://www.springframework.org/webflow
 Changes in version 2.4.0.RELEASE
 -----------------------------------------------
 Move samples to a separate repository https://github.com/SpringSource/spring-webflow-samples
+Upgrade spring-faces to JSF 2 as a minimum requirement
+Upgrade portlet/JSF support to function in JSF 2 environment
 
 Changes in version 2.3.1.RELEASE (Mar 27, 2012)
 -----------------------------------------------