Cleaned up interpreterext.py a bit.  Added the List Grammar along with the Concat token from Joe's GC Branch. Take note I added something in main to process an input file using command line arguments.  sys.stdio.input() does not work in the IDE I am using and from what I read it only used via the command line.  I had to add an option for me to process files.

Added car, cons, cdr and concat from Joe's GC branch.  Car is the only one sort of tested at the moment.  Need to create test cases for the other methods and try them out.  For now this should be a relatively clean Version 1 without GC.