Adds enricher config Propagator.PROPAGATING

- useful for yaml
Failing test demonstrating ResourceUtil not following 301s
Improve HttpLatencyDetectorTest
HttpLatencyDetector enricher uses config keys
Dumpers.logUnserializableChains: handle NPEs
JcloudsLocation: include credentials in getPortMappingsForDocker
Propagator: incorporate review comments
Merge pull request #1333 from aledsage/various/20140423

Various/20140423