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

bugfix: include shift keys in modifier_down

Created by  Kartik K. Agaram  on May 29, 2022
3HDWCPDIQ2R7N63GQIABVE5L63U42CLKNLVJQFKBOZH4BMJQA5XAC
Change contents