make the maude backend output more deterministic

@traiansf please review

The Maude backend had some issues that were making the output to maude JVM dependent. I added some code whose purpose is to ensure that the ordering and numbering of rules is the same accross different Java versions.
Maybe you should ask @grosu if he approves of this change to the code.  Although you detect all errors, it might be reasonable to stop at the first error.