Added support for the writing chunk by chunk

Example:
```cpp
auto awr = session.write_data(key, data, offset, chunk_size);
```
Merge pull request #130 from SaveTheRbtz/master

Recovery, bindings, ioclient and ioserv improvements
Moved merge&split method into IteratorResult. Fixed python logs levels.
Added handling Ctrl+C from detached processes. Added timeout for fetching results from proccesses.
Added check chunk_size on the equality to zero
Merge branch 'feature-libelliptics'
Added handling Ctrl+C in dc2. Fixed skipping equal keys while computing differences between iterator result container.
Merge pull request #132 from shaitan/master

Fixed computing diff. Moved merge from dc/dc2 to iterator. Applied fixes for handling Ctrl+C.
Merge pull request #131 from iderikon/master

Added support for the writing chunk by chunk
Fixed typo in cocaine storage service exception
Removed legacy meta/check/recovery/iterate support

Really, you should use new cool API
Removed example/hparser
Removed DNET_ATTR_DELETE_HISTORY and DNET_ATTR_META_TIMES
Removed dnet_id.type. It was legacy
Temporally removed read_recovery_test

It needs configured multi-groups network
Merge pull request #133 from euroelessar/master

Removed legacy meta/check/recovery/iterate support
Removed sync read and write methods
Removed meta methods from module_backend
Merge pull request #134 from euroelessar/master

Removed last sync methods and fixed module_backend