This PR accumulates many refactorings and small improvements that I did while preparing the next change set of https://github.com/druid-io/druid/projects/2. I finally decided to make them a separate PR to minimize the volume of the main PR.
Some of the changes:
- Renamed confusing "Generic Column" term to "Numeric Column" (what it actually implies) in many class names.
- Generified `ComplexMetricExtractor`
* fix opentsdb emitter always be running
* check if emitter started
* add more details about consumeDelay in doc
* fix possible thread unsafe
* fix fail sending tags whose value contain colon
* Rename io.druid to org.apache.druid.
* Fix META-INF files and remove some benchmark results.
* MonitorsConfig update for metrics package migration.
* Reorder some dimensions in inner queries for some reason.
* Fix protobuf tests.
* opentsdb emitter extension
* doc for opentsdb emitter extension
* update opentsdb emitter doc
* add the ms unit to the constant name
* add a configurable event limit
* fix version to 0.13.0-SNAPSHOT
* using a thread to consume metric event
* rename method and parameter
QiuMM
Roman Leventov
Gian Merlino
kaijianding