Any errors in a schematron schema are not handled

[Conal-Tuohy]

If a schematron schema contains a syntax error, then the p:validate-with-schematron step throws an error which for some reason is not being caught, despite being enclosed in a p:try block with a p:catch. It makes it awkward to debug schematron schemas because although the error appears in the XML service's log, it isn't returned to the client JS like all the other errors.

Maybe a bug in XMLCalabash's implementation of p:validate-with-schematron?