Correct obsolete features in sample dialects

Some sample dialects used extensions that were not part of the design or
whose behaviour or name has changed. These dialects would not compile on
newer versions of the system. They are now corrected.
Add error when "else" used in match

The "else" clause was never part of the matching design, but it remained
in the parser from an earlier approach. This commit adds an explicit
error and suggestion when an "else" clause is encountered.