Add pct.Bytes(): returns human-friendly size like 10.43 MB.
Add data/stats.go: abstracting to test and implement for last send and 1 day.
Make data.Sender use data.SendStats for last and 1d.
Humanize data-spooler-size.
Add pct.Duration(), shorter than time.Duration.String().
Replace Mbps with Utilization and Throughput: former is bytes/(end-begin), and latter is original Mbps.
Fix formatting '63.00001' to '1m3s'.
Fix data-sender-1d.
Fix data-sender-last: use At=end time to include current run values. Tweak status formats.
Rewrite data.Sent() to handle inconsistent reporting.
Use linked list for a radically simpler implementation.
Add test for empty report.
Update go-test dep.
Fix go-test import in data/stats_test.go.
Merge pull request #116 from percona/1d-data-send-stats

PCT-1244: Report data sender stats for last day