fix invalid propagation of node change in cpttemplate - fix issue #143

Fix for issue #143
The problem lied in a wrong propagation of the doc-fragment node change. This propagation is necessary as when a doc-fragment is appended to another DOM element, it becomes empty (and as such useless) - and this happens any time a new piece is generated off-DOM and then inserted back into another DOM elt. The problem is that each node in hashspace needs to keep a reference to the final DOM - so the previous reference to the doc fragment have to be recursively replaced by the new DOM element (that can be also a doc fragment btw.!)

Well.. not sure I was super clear - but feel free to come and see me if you want to know more about this..