Week 4 / Huffman Coding

Raw unzip from http://spark-public.s3.amazonaws.com/progfun/assignments/patmat.zip
Implement weight and chars
Implement times() function
Implement makeOrderedLeafList
Implement singleton
Implement combine
Implement until
Implement createCodeTree
Implement decode
Implement encode
Implement quickEncode

codeBits is still an exhaustive search (maybe use the weights?)

First submission (9.7/10)
Fix Nil list bug in times()

Second submission (10/10)
Build the lists up the right way around