Modify TsdbQuery to run the query scanner asynchronously
Add Query.runAsync() method
Deprecate UniqueIdInterface.

This interface has never been useful and will eventually be removed.

Change-Id: Ie63411f17486074a4dd96829af09d172363cc1f2
Factor out a bit of UniqueId code.
Add RowKey.metricNameAsync() to fetch the metric name asynchronously from a
row key
Add Tags.getTagsAsync() to resolve the tags asynchronously from a row key
Fix RuntimeException catching in TsdbQuery.run() after adding async code
Add async methods for all DataPoints implementations so that the full query
path can be converted to async code.
Modify GraphHandler to execute queries asynchronously.
Fix Tags deferred grouping for OpenJDK whining