- can use operators "+" (Sequence) and "|" (Alternative) for constructing parsers in Python; better testing suppoer

- example MLW extended by adding rudimentary testcases

- 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.

moved code generation of factory functions from dsl.py to ebnf.py; finished testing function at the end of parser.py (not yet tested)

- 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 (primitive) name mangeling to EBNFCompiler to avoid name conflicts with names used in the grammar definition

- Refactoring: AST-Transformation must now be passed as a function to full_compilation(), compileDSL etc. This allows more flexibility in doing
custom validation of the syntax tree before, after or while AST transformation.

- 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

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