Added support for the writing chunk by chunk

Example:
```cpp
auto awr = session.write_data(key, data, offset, chunk_size);
```
Added check chunk_size on the equality to zero
Merge branch 'feature-libelliptics'
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