- Method add_node has been deprecated in favor of
classify_data_node and append_node
	- keep_always_whitespace_mode has been dropped in favor
of the new Pxp_yacc.config option drop_ignorable_whitespace
	- create_element_node: accepts the arguments ~att_values
and ~valcheck. The first of them contains the already preprocessed
and normalized attribute values as att_value (and not as string).
The latter may be used to switch off the validation of attribute
lists.
	- validate_contents, validate_attlist, validate: these
are now the core validation methods
	New methods:
	- complement_attlist
	- improved namespace_manager
	- delete_nodes, insert_nodes
	- set_data
	- set_attributes now official
	New functions:
	- strip_whitespace
	- normalize
	- validate


git-svn-id: https://godirepo.camlcity.org/svn/lib-pxp/trunk@358 dbe99aee-44db-0310-b2b3-d33182c8eb97