This includes better dependency aggregation than before. For example,
you no longer need mysql to view the dependency graph, as the in-memory
server supports aggregation now. Also, if you log "ca" on a root span,
the associated service will show on the dependency graph on the far
left. This allows you to show uninstrumented clients of note. Similarly,
if you log "sa" on a leaf node, the destination will show on the far
right. You'd use "sa" for uninstrumented services like databases, auth
servers or cloud apis.
Note: 0.5.2 uses spring boot 1.3.2
Zipkin 0.4.1 obviates some duplication of configuration. It is also the
first version that's published as a docker image.
By switching to the published image of zipkin-java, we can be more
consistent, as `spring-cloud-sleuth-zipkin-stream` is derived from that,
not the scala query service.
