Week 6 / Anagrams

Raw unzip from http://spark-public.s3.amazonaws.com/progfun/assignments/forcomp.zip
Trailing whitespace fixes
Implement wordOccurrences
Implement sentenceOccurrences
Implement dictionaryByOccurrences
Implement wordAnagrams
Implement combinations
Implement subtract
Implement sentenceAnagrams
Refactor dictionaryByOccurrences to use groupBy
Refactor subtract to use an intermediate map
Add comments to combinations
sentenceOccurrences should handle empty sentence
Refactor wordOccurrences to use groupBy

Grader instists groupBy must be used, although I'd venture my merge implementation is faster