Fix OrderByColumnSpec cacheKey.
Merge pull request #663 from metamx/fix-obcs-cache-key

Fix OrderByColumnSpec cacheKey.
support both rejectionPolicy and rejectionPolicyFactory in serde
fix deadlock condition that can exist in the coordinator
Merge pull request #670 from metamx/fix-deadlock

fix deadlock condition that can exist in the coordinator
add more config to router strategies; fix bad test
fix defaults
fix test
fix test again
fix bad defaults
clean up some redundant code
make things immutable
Change merged-segment-removing behavior in RealtimePlumber.

Old: Merged segments are deleted upon successful push, or on IOException.
New: Merged segments are deleted on any Exception, but NOT successful push.

Deleting a merged segment means that the next merge-and-push run will try to
push it again. So we want that to happen if there was any sort of Exception.
We *don't* want it to happen if the merge-and-push was successful, since in
that case, we are just waiting for historical nodes to load the segment. It
might take a while, but there's no reason to re-push while waiting.
Fix conditional.
Merge pull request #673 from metamx/rt-plumber-merge-behavior

Change merged-segment-removing behavior in RealtimePlumber.
Merge pull request #672 from metamx/router-strat

Add more config to router strategies; fix bad test
prepare for next release
[maven-release-plugin] prepare release druid-0.6.139
[maven-release-plugin] prepare for next development iteration
add note on filing bugs