Revision control
++ <?xml version="1.0" ?>
++ <scxml xmlns="http://www.w3.org/2005/07/scxml" version="1.0"
++ datamodel="ecmascript" name="StateMachine">
++ <scxml xmlns="http://www.w3.org/2005/07/scxml" version="1.0"
++ datamodel="ecmascript" name="NestedStateMachine">
++ </scxml>
++ </scxml>