Fixing deployment events handling for apps in groups

[dankraw]

fixes #35

[janisz]

Custom names looks for the first sight looks easy, but now we get more and more complicated code. There could be more corner cases than we previously thought. We need to discuss this feature.
I'll test this PR tomorrow, code looks good 👍

[adamdubiel]

Maybe we should pivot now and make it as simple as possible. @dankraw suggested some simple k/v mapping, Consul has own k/v so why not use it if we go this way.

[dankraw]

OK, so as we spoke, we're gonna keep the current implementation for v0.3.x and maybe return to the KV-store idea in the future if there are more issues with parsing large events / weird corner-cases etc.
The KV-store integration is not cheap either as we thought at first. The data has to be put there depending on some stimulus/app configuration, it needs to be replicated to all datacenters, plus we would have to rethink how to support renaming of services.