enable snappy compression for memcached results
swap out snappy for LZ4
Merge pull request #155 from metamx/snappy-cache-compression

enable cache compression for memcached
add delegating executor service and fix bug with query priortization
Merge branch 'master' of github.com:metamx/druid
1) Fix bug with Master stopping trying to be Master after he losses it once
Merge branch 'master' of github.com:metamx/druid
[maven-release-plugin] prepare release druid-0.5.3
[maven-release-plugin] prepare for next development iteration