Stable API.

Added SyncProducer.
Renamed public methods:

• GetConsumer -> Consumer
• GetProvider -> AsyncProvider, SyncProvider.

Fixed reconnection tests

Merge pull request #22 from cheshir/improve_coverage

Improved coverage.

Fixed support of JSON configs.

0.4.4

Fixed linter's warnings.

Stable interface

Package interface was edited last time.

• We used errors instead of bool values as a result of Get... methods.