Toy brainf**k interpreter; example app that can be modified without restarting

clean up repl functionality

Now we have separate keywords for returning vs drawing something.

Created by  Kartik K. Agaram  on May 11, 2022
D2GCFTTT2RNUBFB243YTA4F2H5ZXFTFHBSKHLZ2CX4JSKRZFTUUQC
Change contents