Add support for optional debug parameters
Update debug documentation for clarity and accuracy
Add printFields and printTuple interval support
sumByLocalKeys, Counters and Task Numbers
Adds head and sortedTake to KeyedList
Pull out scalding-json as a separate module.
Add scalding-json to project/Build.
Added Test for CascadingJob Through Tool.main
Fix CascadeJob NPE
- Overrode validate to iterate over def jobs to call validate on each
  job.
Clean build dependencies.
Remove jackson dependency from scalding-core.
Generate simple json JobStats in Tool.
adds quotes around json value.
Only add quotes fro strings.
Merge pull request #705 from twitter/klin_scalding_json

Pull out scalding-json as a separate module.
Merge pull request #678 from pcting/fix/cascade-job-flowdef-npe

Fix CascadeJob FlowDef NPE
Add tests for head/sortWithTake
Fix KeyedList variance and joining
update comment
Revert the KeyedListLike, just use KeyedList