Revision 554101

Bugzilla 41656
        Refactoring in the fo package:
        -> removal of the childNodes instance member in fop.fo.FObj
        -> addition of a firstChild instance member in fop.fo.FObj
        -> addition of a siblings instance member in fop.fo.FONode
        -> addition of a FONodeIterator interface in FONode + corresponding implementation in FObj
        -> changed implementations of FObj.addChildNode(), .removeChild() and .getChildNodes()