prefix in builded xpath expression.
* Update test according to this modification

this avoid reading entirely the files if they differ during reading.
- Use parser with remove_blank_text flag to normalise output and c14n.
- Do not append tail to xupdate elements if not needed.

- Support xupdate:insert-before element
- Order attributes updates

- Calculate position of node regarding his parent not by counting his position in child_list
- All equals nodes (c14n) are not compared anymore
- Fix last tested bugs

- replace distutill with setuptool 
- append test-cases using docstring
- append buildout setting
- append interface
- eggify

Using both library make conflicts, so each Lib should use his own implementation. 4Suite require creating node by Qname (with namespace URI)