Added empty C++ merge method. Fixed run_iterator in dc2
Separated process_address into iterate_node_and_sort and process_diff. Computes iterate result in pool for all node includes local.
Fixed process_diff for empty local or remote results
Remove useless cycle.
Optimized by using Pool.imap_unordered and Pool.map
Added interrupting iterator execution on server-side if client connection has been closed.
Added comment and record to log when interrupting iterator.
Added generic monitoring and dc2 monitoring impl.
Fixed output for stats: increased width. Added sending monitor info from dc script
Added recovery type to monitor statistics output. Changed apply_async to imap_unordered.
Added ready for async_result. Added extra write_data
Added bulk_read_async and write_data_async and added iterating ability to returned results. Fixed bugs
Added missed monitor.py. Optimized monitor output: leave only important counters and timers.
Merge pull request #142 from shaitan/master

Monitor, async bulk_read and write_data.