- example MLW extended by adding rudimentary testcases

- 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.

tests/test_syntaxtree.py to syntaxtree.py

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

- potential infinite loops are now caught when running parser and an error is reported; bug fixes, tests

- DSLsupport.run_compiler now produces callable DSL compiler script stubs; code reorganization all DHParser modules moved to a subdirectory containing the DHParser package; dhparser.py script remains in the main directory