Recovery: Added draft of sdc recovery.

Conflicts:

	recovery/elliptics_recovery/iterator.py
Python: Added pickling elliptics.IoAttr and elliptics.Time
Merge branch 'master' of github.com:reverbrain/elliptics
Python: Added id.py and allow specify elliptics.Id by hash string or int/long value of id.
Recovery: Added ability to set current value of statistic in case incrementation isn't possible. Added 'iterated_keys', 'filtered_keys', and 'total_keys' to iteration statistics.
Recovery: replaced dc by sdc. Added ability to split big files while merge recovery (dc recovery will get it soon).
Merge branch 'master' of github.com:reverbrain/elliptics
Recovery: added dc_recovery.py - build-in custom recovery function for dc. Added recovery.qdoc.
Cache: added setting n->need_exit before stopping cache: it is used by life_check thread. Tests: fixed moving group into backend section.
Tests: fixed executing run_servers and forking dnet_ioserv.
Fixed compile error
Merge branch 'master' of github.com:reverbrain/elliptics
Merge branch 'master' of github.com:reverbrain/elliptics
Tests: provide LD_LIBRARY_PATH into execve child.
Merge pull request #451 from shaitan/master

New DC recovery and fixes