split compileEBNF into two functions: compileEBNF and compile_parser; adjustments for compatibility with pypy3 / python 3.5

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

- 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