Initial commit of adding histogram functionality to the DoubleRDDFunctions.
Add tests for the Java implementation.
CR feedback
Remove extranious type definitions from inside of tests
Remove extranious type declerations
Remove explicit boxing
Add spaces
Fix the test
Merge pull request #86 from holdenk/master

Add histogram functionality to DoubleRDDFunctions

This pull request add histogram functionality to the DoubleRDDFunctions.