syntaxtree, class Node: XML-output now puts tags and content of the innermost node on one line for better readability

- virtualized Parser.__class__.__name__ by introducing Parser.ptype (which by default is set to Parser.__class__.__name__)
- removed all isinstance(node, ...) statements from ebnf.EBNFCompiler, because this does not work with mock trees which are be needed for testing.

- better syntaxtree.mock_syntax_tree() generation: Can now read actual ASTs in S-expression form. Useful for testing of AST-transformation or -validation as long as these do not call isinstance() on any parser.

- added `start_parser` parameter to `GrammarBase.parse` in order to allow fine grained testing of ENBF syntax descriptions;
- added `dsl.suite_outdated`
- further corrections

- renamed parser.py to parsercombinators.py to avoid possible name conflicts with the parser module from the Python standard library

- Grammar class now defines left und right default white space handling, so it is usually not necessary any more to specify whitespacehandling in the constructor of RE- and Token-objects.

- additions to AST-transformation-table of MLW_compiler.py

- some smaller bugs fixed

- XML-output for MLW-Test (still based on the concrete syntax tree!)

- Require()-Parser now yields "fatal_error" - otherwise it would be overlooked. (Parser-Error reporting in general needs to be reconsidered...!)
- testbed for MLW example optimized

- EXPERIMENTELLER Debugging-Code für den Aufrufer-Stapel der Parser in der left_recursion_guard()-Funktion.
- Refactoring, u.a. ParserRoot -> ParserHeadquarter
- compilierungsscripte für a) MLW-Grammatik b) MLW-Einträge mit dieser Grammatik
- Grammatik für MLW erweitert und Beispiel "facitergula.mlw" ausgebaut.