implement BusClient connect, disconnect and publish
replace ami.event Event with ami.client Message

no need for a custom class, a namedtuple does the job
inject xivo_bus.ctl.client.BusCtlClient in BusClient
improve test coverage on parser
minor formatting fixes
add missing assertion
harmonize {,dis}connection logging
add exception handling in BusClient
improve exception handling in BusClient
fix tests in BusClient
Merge branch 'bus-integration-3'