make prioritized executor service listenable
allow forcing all tasks to be prioritized
fix jetty threads getting stuck

Fix Jetty threads getting stuck on exceptions
make MetricsEmittingExecutorService listenable
use Guava's ForwardingExecutorService instead of DelegatingExecutorService
fix broken CombiningSequence.toYielder behavior
tests must not assume findOvershadowed ordering
always use ByteCountingLRUMap.remove() to remove
Merge pull request #538 from metamx/fix-jetty-exception-handling

fix jetty threads getting stuck
union query fix and a broken test
clean up event receiver firehose factory
Merge branch 'master' of github.com:metamx/druid
add sanity unit tests
add header
Merge pull request #543 from metamx/fix-combining-sequence-yielder

fix broken CombiningSequence.toYielder behavior
Merge pull request #545 from metamx/union-query-fix

Union query fix
update java-util and add more merge sequence tests
more comprehensive merge sequence tests
ignore jetty exception test for now
[maven-release-plugin] prepare release druid-0.6.109