Python: changed counters output to dict.
Merge pull request #277 from shaitan/python

Python: changed counters output to dict.
Python: elliptics.Data added to_string and __repr__ methods which returns string representation of internal data
Python: Removed elliptics.Data and uses python string instead of. Fixed specifying object method as callback for elliptics.AsyncResult.connect.
Merge pull request #278 from shaitan/python

Python: Removed elliptics.Data and uses python string instead. Fixed specifying object method as callback for elliptics.AsyncResult.connect.