Pytests: moved  fixture to global conftests. Disabled srw for test cluster in test_specific_cases. Cleaned up pytests code.
Pytests: added iterator tests.
config: use uint32_t for parsing group from config - disallow setting negative group.
bindings: added start_time and end_time methods for async_result: both for C++ and Python bindings. They returns timestamps when async result was created and finished.
Fixed calculation tnsec of elapsed_time.
python: fixed gil_guard
python: made elliptics.Id to be initialized by any iterable object and group
recovery: replaced cPickle by msgpack for packing intermediate results
recovery: added 'total_keys' statistics that shows how much keys should be recovered/processed
recovery: added 'recovery_speed' and 'iteration_speed' to statistics. Both values are mesuared in records per second.
iteration: added new iteration flag: DNET_IFLAGS_NO_META which turns off reading extended header from blob and speedups iteration, but all keys that will be returned by such iteration will have empty metadata (timestamp and user_flags).
recovery: added '-M' option to dnet_recovery which speedups iteration phases of recovery but sacrifices checking metadata. Recovery with this option will not check metadata, will not replace old records by new ones and will only copy some available replica of keys to groups which do not have these keys.
pytests: updated some test cases of test_recovery to use new '-M' option
pytests: added case to test_session_iterator that check iterating with no_meta flag
iteration: removed double checking of ranges - keys is already filtered in eblob.
recovery: added recovery_speed to merge stats.
recovery: used total_size instead of size for determining record size.
recovery: escaped dumping keys that allready consistent in all groups
core: fixed broking API/ABI.
python: limited types of object that can be used for elliptics.Id initialization
Fixed typo
tests: updated description of test_session_iterator cases.
recovery: fixed recovering keys which have several alive copies at one backend.
Merge pull request #565 from shaitan/master

Fixes & updates