Merge branch 'release-0.76'
Merge branch 'development'
Read timeouts from config before creation elliptics session
Version up to 0.76.4
MDS-432: app's io-loops are stopped in app d-tor

Proxy destroys elliptics io-loop to stop handlers processing before
being destroyed itself
Merge branch 'feature-mds-432' into development
Version up to 0.77.1
Elliptics sessions are destroyed before node
Merge branch 'feature-mds-432' into development
Merge branch 'development' into release-0.77
Version up to 0.77.2
handystats: update to handystats v2

Request metrics collection mechanics is performed via request_wrapper.
Upload request instrumented.
Handystats' file_logger added ("stats-log" config section).

Collected metrics:

* mds.<request>
  -- rate for request (get, upload)

* mds.<request>.<response code | group>
  -- rate for response code (100, 201, 404, etc.) or group (1xx, 2xx, 3xx, 4xx, 5xx)
     of request (get, upload)

* mds.<request>.<2xx | 3xx>.time
  -- timings for response code group (2xx, 3xx) of request (get, upload)
  -- 'frequency' statistic may be used for rps
handystats: forward arguments in request_wrapper constructor.
handystats: handystats core and stats logger initialization moved to separate functions.
handystats: base_request_wrapper's virtual destructor added.