Validate branches of a document

[GoogleCodeExporter]

Allow a command-line parameter to validate branches of a document.

Paul Grosso of PTC has requested this and has code to provide. A new parameter 
root-node-to-validate-xpath parameter  is used. 

Original issue reported on code.google.com by [email protected] on 9 Jul 2010 at 5:58

[rjelliffe]

Seems reasonable. Need to track down code.

[PStellmann]

Just as a marker: There is a correlation (no conflict though) with the @followup from #18. So when starting the validation in the middle of a document you also need to check if there is an ancestor element with a matching rule that has @followup='skip-content'. In such a case the validation would need to be skipped (for this pattern).