Rework sample app

[dariuszseweryn]

Summary

The sample app is a simple application that uses the library. As a sample it does not contain any good architectural patterns as it is not the point of the sample. Unfortunately this leads to a lot of questions on stackoverflow from people who do not know how to address typical use-cases like:

• binding the connection lifecycle to something other than an Activity
• having multiple inputs of events that should be handled by the RxBleConnection (i.e. sharing the connection)
• etc.

The idea is to either rework the sample app to something that is more complex but shows better architectural approach or gather a list of good articles that would show good ways of usage.

[RobLewis]

Regarding your first point, I'd love to see coverage of running Observables in background Services.