Implement DeleteIdleStats
Fix typo of gauges
Add sum/count_ps to timers and fix a bug where percentile can't be equal
to the min value in stat_accum_input
Document `-config=/dir` option.
Issue #722 Add user agent normalization to the Nginx decoder
Initial ProcessDirectoryInput implementation, along w/ significant
changes to ProcessInput, ManagedCmd, and CommandChain.
Update the unit test to verify the FxA use case.
Clarity fixes in docs / comments, cleaner filepath API usage when
calculating ProcessDirectoryInput file and folder paths.
Merge pull request #725 from mozilla-services/issue_722

Issue #722 Add user agent normalization to the Nginx decoder
Merge pull request #726 from mozilla-services/process-directory-#477

Initial ProcessDirectoryInput implementation, along w/ significant
Merge pull request #723 from mozilla-services/doc-config-dir

Document `-config=/dir` option.
Fix the cbuf aggregation description (FxA request)

e.g. 1 day aggregation for the last 365 days
instead of
86400 second aggregation for the last 8760 hours
Merge pull request #728 from mozilla-services/dashboard_cbuf_description

Fix the cbuf aggregation description (FxA request)
Don't dynamically allocate slice
Make new tests reliable
Add changelog entry and docs entry
Merge pull request #720 from dctrwatson/more-timer-stats

Add sum/count_ps to timers and fix a bug where percentile can't be equal
Merge branch 'dev' into deleteidlestats

Conflicts:
	CHANGES.txt
	pipeline/stat_accum_input.go
Delete idle gauges (when configured)
Merge pull request #693 from dctrwatson/deleteidlestats

Implement DeleteIdleStats