This change adds more data to the stream with {"type":"Ping"}
so (I believe) the existing dashboard client will discard it,
but stay alive.

Fixes gh-264

Fixes gh-259

If you are using AMQP there needs to be a ConnectionFactory (from
Spring Rabbit) in the application context. If there is a single
ConnectionFactory it will be used, or if there is a one qualified as
@[Hystrix,Turbine]ConnectionFactory it will be preferred over others,
otherwise the @Primary one will be used. If there are multiple
unqualified connection factories there will be an error.

See https://github.com/spring-cloud/spring-cloud-bus/issues/13

 fixes gh-147

This change adds an ApplicationListener that sets some high priority
properties in the Environment to allow server.port and management.port
to keep their usual meaning, but have server.port apply only to turbine.
Actuator endpoints can be enabled with management.port (different to
server.port otherwise there will be a conflict between Netty and Tomcat).

Fixes gh-143, fixes gh-140

Fixes gh-126

fixes gh-108