Refactor BasicRollup output serializer and fix a bug in tests
Fix bug in HistogramRollup when number of bins computed could be -ve
Expose get methods for histograms in AstyanaxReader and RollupHandler
Add histogram JSON output serializer and test
Expose HTTP endpoint and add HTTP handler for histograms
Add tests for hisotgrams HTTP endpoint
Add changelog to CHANGES
Switch to codahale metrics instead of yammer
Use Timer.Context instead of TimerContext (codahale migration)
Improve JSONBasicRollupOutputSerializer tests
Merge pull request #166 from lakshmi-kannan/bf_read_api_for_histograms

Feedback: Read API for histograms