Typo fixes
Small fixes, use new calculation method for nfs v3 latencies.
Use new calcuation method for get_nfsv3_perf_stats() + cleanups
Use new calcuation method for get_aggregate_perf_stats() + cleanups
Define counters for get_volume_perf_stats() + cleanups
Convert to new way to render perf data
Added volume stats (get_volume_perf_stats())