Merge pull request #559 from shaitan/master

pytests: fixed broken index tests - use common cluster for all test and ...
speed up dc recovery as don't spend time on pickling/unpickling data and concatenate files via cat.
Change file concatenation from calling cat to python file read+write
use shutil.copyfileobj to concatinate files
lookup: extended lookup address to return dnet_addr, not address string
v2.26.3.33
Merge branch 'master' of https://github.com/reverbrain/elliptics into dc-recovery-fix-on-cat
remove extra bracket
Disable only non-disabled backends at cleanup.
config: do not reparse config at each backend init - only if config was modified. Removed useless copying of an array at config methods.
Merge pull request #563 from shaitan/master

Optimized dnet_ioserv startup
Fixed code indent
Merge pull request #564 from shaitan/master

Fixed code indent
Added option for dumping into text file all iterated keys
Switched pickle protocol to binary to reduce size of temp files and reduce processing time
Made dumping key enabled by default, to disable it introduced new option -> -u
don't add option for key dumping in dc_recovery
removed multiple context expression for python 2.6 compatibility
don't set ctx.dump_keys on dc_recovery
removed multiple context expression for python 2.6 compatibility