Add tundra.tn.document.error:exists - returns true if any errors (of a given class, if specified) are found on the given bizdoc
Add tundra.tn.support.document.strict:check - throws an exception if the given bizdoc contains any errors matching the given classes
Add support for 'strict' mode processing of bizdocs to top-level services and their queue and reliable counterparts; closes #12; closes #14