add hw01 pdf
initial file
exercise 1 tests and function shells
add decimate function
fill in lastDigit
add reinforce function
finish dropLastDigit and Exercise 1
add toDigits which is the decimate function I made earlier plus a check for negative numbers
add exercise 3 failing tests
finish doubleEveryOther and exercise 3
exercise 4 failing tests
finish sumDigits and exercise 4
failing tests for exercise 5
finish validate and exercise 5