ContextResources shouldn't programmatically insert data into the result tree. Instead the framework should automatically serialize data objects. Thus it should be possible to create a XML schema definition, which describes the expected tree and can be used to validate the XPath expressions working on the tree. The ContextResource interface should be marked as deprecated.
The Pustefix editor should be extended to validate XPath expressions against the XML schema describing the result tree. It also should ensure that for each input element an according IWrapper attribute is exisiting.
Pustefix already supports automatic data object serialization and the ContextResource interface is deprecated (see #25).
