GS Collections Kata w/ JCF Solutions

[Raab, Donald]

I checked in new solutions using the latest b73 binary.  I wound up implementing b72 and b73 within a 48 hour period so it was interesting to see the evolution of user experience.  I've shared a few rounds of the evolution of the kata using the binary snapshots here.

b73 (explode/collect):

https://github.com/goldmansachs/gs-collections-kata/blob/solutions-java8-jcf/src/test/java/com/gs/collections/kata/Exercise9Test.java

b72 (mapMulti/accumulate/into:):

https://github.com/goldmansachs/gs-collections-kata/blob/105a5dd64aafcf2a0fe3bebda6c120a7e759e2b7/src/test/java/com/gs/collections/kata/Exercise9Test.java

Prior: (flatMap/tabulate/into):

https://github.com/goldmansachs/gs-collections-kata/blob/d9e4f006012d9b5c9e2ede0e78e426b94b740890/src/test/java/com/gs/collections/kata/Exercise9Test.java

Prior: (flatMap/groupBy/into)

https://github.com/goldmansachs/gs-collections-kata/blob/9c344e12e3f502c9f9f2961135a6b095207f9d88/src/test/java/com/gs/collections/kata/Exercise9Test.java

First binary version I tried: (flatMap w/ Mapper/no groupBy available/into)

https://github.com/goldmansachs/gs-collections-kata/blob/dd3055771cb09c8a2ed1fc9d9ebe9cb09a8e2930/src/test/java/com/gs/collections/kata/Exercise9Test.java