Add auto-pdb fallback when not in translated mode for target
Add test for external and environmental stuff

Here: Commandline
Preps for benchmarks

Includes
 * In-VM execution of racket to produce .json files
 * Marginal support for commandline options (e/f/u/t/ etc)
 * Character literals
 * Restructured folder, just execute

         PYTHONPATH=$PYPY python pycket myfile.rkt

   in the top folder.
 * Access to commandline arguments
 * (a possible rpython bug....)