Implement the following opcodes:
- push and pall
- pint
- pop
- swap
- add
- nop!
Implement the following opcodes:
- sub
- div
- mul
- mod
- '#' comments
- pchr
- pstr
- rotl
- rotr
- stack and queue
Implement the following BrainFuck scripts:
- bf/1000-school.bf: print school
- bf/1001-add.bf: add 2 digits
- bf/1002-mul.bf: multply 2 digits result < 10
- bf/1003-mul.bf: multply 2 digits result > 10