Gauge vs Cumulative. (#65)
Gauge vs Cumulative. (#65)

* Gauge vs Cumulative.

- Split TimeSeries into GaugeTimeSeries vs CumulativeTimeSeries.

- Merge GaugePoint and CumulativePoint into a single Point message
  to minimize validation.

- Remove TODO: we don't validate keys or values.
census-instrumentation/opencensus-proto