some brief nitpicking re p:insert and p:add-attribute

some assumptions;

* p:insert only deals with elements ...

* also p:add-attribute could just as equally be p:insert-attribute

why not rename to

    p:insert-element
    p:insert-attribute

so they are next to each other in the dictionary ;)  .... also might
consider a p:insert-text, p:insert-comment, and p:insert-pi if we are
to be complete (though at this stage quite happy to leave this to
extensions).

Jim Fuller