Tests option is declared with a correct boolean value in @required
Test ab-option-005.xml is expected to fail with error code err:XS0077.
<p:declare-step xmlns:err="http://www.w3.org/ns/xproc-error" xmlns:p="http://www.w3.org/ns/xproc" version="3.0">
   <p:output port="result">
   <p:option name="option" required="no">
   <p:identity>
      <p:with-input>
         <doc/>
      </p:with-input>
   </p:identity>
</p:declare-step>
Fix namespace declarations
Reversed @pipe-substructure. (->Prague 2018)
added new tests