Initial commit for hw4
Implementing problem 1 (sequence function)
Impelemnting problem 2 (string-append-map)
Implementing problem 3 (list-nth-mod)
Removing unnecessary files
Impelemnting problem 4 (stream-for-n-steps)
Implementing problem 5 (funny-number-stream)
Implementing problem 6 (dan-then-dog)
Implementing problem 7 (stream-add-zero)
Impelementing problem 8 (cycle-lists)
Implementing problem 9
Implementing problem 10
Fixing bugs