- DHParser/parse.py Parse.__init__() and Parse.reset() move clearing of cycle-detection buffer to __init__ to avoid infinite loop if reset() is called during the Parser.apply() for some reason

- DHParser/parse.py MetaParser, OneOrMore, ZeroOrMore: multiple infinite loop error messages at the same location will be avoided.

- DHParser/parse.py: bugfix MetaParser.return_values() empty nodes will now be properly deleted (unit test added)