Add units to measurements where appropriate.

  - Post these units to Librato
    - They don't make sense anywhere else at the moment.
Multiply by 100 for percentage calculations through SHH_PERCENTAGES
Downcase protocol for output sockstats
Attach more units to measurements.

- BREAKING Change: total_bytes to total.bytes in df_poller
Merge branch 'issue-4' into rc-0.5.0
Merge branch 'librato-units' into rc-0.5.0

Conflicts:
	df_poller.go
	mem_poller.go
	sockstat_poller.go
Release 0.5.0