[stateless] WICKET-5400 Behaviors#internalAdd(Behavior) erroneously gets id for stateless behaviors

Explicitly get an id for the stateless behavior
[core] Build against 6.13.0-SNAPSHOT
[jquery-parent] Fixes #276 - Upgrade jgrowl.jquery.js to latest stable (1.2.13)
Improved validation support
Test case fixing...
Fixed package name to match folder structure

As package declaration was different than folder structure, source lookup does not work in IDEs like Eclipse.
Fixed shiro exception on logout when using "native" shiro session

subject.logout() already invalidates session and subsequent call to Session.get().invalidateNow() will cause shiro exception when using "native" shiro web sessions. See issue #277 .
Added FeedbackMessage.SUCCESS to JGrowlFeedbackPanel
Added FeedbackMessage.SUCCESS to JGrowlFeedbackPanel

Indexed JGrowlFeedbackPanel.html to better spot the HTML doc structure
[scala] Update the Maven archetype to Scala 2.10
[scala] minor improvements in WicketDSL. Fix the SBT build
Added JavaDoc
Added support for variations in ModalContentPanel. String variation is added with appropriate getters and setters.
Renamed trackModalVisit(IWicketModalVisit) to preShow(ModalContentPanel) to reflect the need for a more generic
hook into the lifecycle of a modal dialog. eg., can set the markup variation on a MessageBox to allow customization of
the MessageBox appearance etc.,
Added support for validators' resource bundles
Code refactored to clean it and avoid API breaks.
[datastores] Add implementations of IDataStore based on Memcached and Apache Cassandra
[datastores] Reimport the datastores
[scala] Add src/main/resources as resource explicitly
[datastores] Extract the session resources management to a specialized class

Next step: implement resources constrains per http session (as PageWindowManager does for DiskDataStore)
[datastores] Implement session resources management for Memcached data store