Removed aggregate and added aggregators.
Add overridden addDataPoint() methods to Metric with the timestamp being the current time as suggested by Glenn.
Added missing method to create a sum aggregator in AggregatorFactory. Updated documentation to show new addAggregatorMethod.
Merge remote-tracking branch 'upstream/master'

* upstream/master:
  Added missing method to create a sum aggregator in AggregatorFactory. Updated documentation to show new addAggregatorMethod.
  Add overridden addDataPoint() methods to Metric with the timestamp being the current time as suggested by Glenn.
  Removed aggregate and added aggregators.