add grammar file name in the error output of the bootstrap parser
refactor syntax.py to split the components to classes of their own
fix critical parser bug
fix parser bug: allow $INITIAL as %begin argument in the self-hosting parser
improve error messages in the self-hosting parser
improve some error message texts, some source format fixes
also del the self-hosting parser after use in __main__.py
check for undefined metas in the self-hosting parser