added tests for localMaxima and histogram
added tests for localMaxima
toDigits and toDigitsRev impls
completion of exercises 1-4
hanoi implementation
improved doubleEveryOther impl
exercises 1-5, week 2
week 3: implementing 'skips' in terms of 'skip'
week 3: implementing 'localMaxima' in terms of 'chunk'
week 3: solving 'histogram' in terms of 'digitFreqs' and 'rows'