Miscellaneous AJAX bugs

There are a couple minor AJAX-related bugs:

• h:commandButton needs to append "return false;" for onclick when a behavior chain is present.
• if <f:ajax> disabled=true, the AJAX call is still emitted.
• Possible issue with <f:ajax> execute="multiple ids". Seems the javax.faces.partial.execute request param may differ from Sun RI.
• Unable to restore StateHolder when listener is specified for <f:ajax>.
• <f:ajax> onevent not being handled.
• <f:ajax> onerror not being handled.
• <f:ajax> render="@all" not working correctly.
• <f:ajax> render="@form" not working correctly.
• <f:ajax> render="@this" not working correctly.