relative d:ref/@hef, try/catch for px:info, and tests

 - fileset-add-ref: d:ref/@href made relative to base-uri(parent::d:file)
 - fileset-copy: catching dynamic error thrown from px:info when
   directory doesn't exist
 - added test script for fileset-add-ref and updated tje test scripts
   so that they are easier to run. Run src/test/resources/test.xpl to
   run all the tests and generate a report in file:/tmp/report.html
Merge branch 'master' into fileset-file-refs
Merge pull request #3 from daisy-consortium/fileset-file-refs-and-tests

Made d:ref/@href relative, added try/catch for px:info, modified tests