Fetch pack cleanups:
* Limit backed up fetch pack requests
* Cleanups
* Dispatch fetch packs sooner
Make I/O latency available through server_info
Reduce number of async fetches
[WIP] Add multi-sample interface to load monitor
[WIP] Node store monitoring
Update .gitattributes
Merge commit 'b24a2b9c52db2bd93430c248fb8943738158b08d' as 'src/snappy/snappy'
Add snappy compression integration
[WIP] Enable leveldb snappy. Configure from config.cfg