HLS video handling/storage/state refactor (#151)

* WIP with new transcoder progress monitor

* A whole different WIP in progress monitoring via local PUTs

* Use an actual hls playlist parser to rewrite master playlist

* Cleanup

* Private vs public path for thumbnail generation

* Allow each storage provider to make decisions of how to store different types of files

* Simplify inbound file writes

* Revert

* Split out set stream as connected/disconnected state methods

* Update videojs

* Add comment about the hls handler

* Rework of the offline stream state.  For #85

* Delete old unreferenced video segment files from disk

* Cleanup all segments and revert to a completely offline state after 5min

* Stop thumbnail generation on stream stop. Copy logo to thumbnail on cleanup.

* Update transcoder test

* Add comment

* Return http 200 on success to transcoder. Tweak how files are written to disk

* Force pixel color format in transcoder

* Add debugging info for S3 transfers. Add default ACL.

* Fix cleanup timer

* Reset session stats when we cleanup the session.

* Put log file back

* Update test

* File should not be a part of this commit

* Add centralized shared performance timer for use anywhere

* Post-rebase cleanup

* Support returning nil from storage provider save

* Updates to reflect package changes + other updates in master

* Fix storage providers being overwritten

* Do not return pointer in save. Support cache headers with S3 providers

* Split out videojs + vhs and point to specific working versions of them

* Bump vjs and vhs versions

* Fix test

* Remove unused

* Update upload warning message

* No longer valid comment

* Pin videojs and vhs versions

utils/performanceTimer.go

@@ -0,0 +1,50 @@
+package utils
+
+import (
+	"sort"
+	"time"
+)
+
+// The "start" timestamp of a timing event
+var _pointsInTime = make(map[string]time.Time)
+
+// A collection of timestamp durations for returning the average of
+var _durationStorage = make(map[string][]float64)
+
+// StartPerformanceMonitor will keep track of the start time of this event
+func StartPerformanceMonitor(key string) {
+	if len(_durationStorage[key]) > 30 {
+		_durationStorage[key] = removeHighAndLow(_durationStorage[key])
+	}
+	_pointsInTime[key] = time.Now()
+}
+
+// GetAveragePerformance will return the average durations for the event
+func GetAveragePerformance(key string) float64 {
+	timestamp := _pointsInTime[key]
+	if timestamp.IsZero() {
+		return 0
+	}
+
+	delta := time.Since(timestamp).Seconds()
+	_durationStorage[key] = append(_durationStorage[key], delta)
+	if len(_durationStorage[key]) < 10 {
+		return 0
+	}
+	_durationStorage[key] = removeHighAndLow(_durationStorage[key])
+	return avg(_durationStorage[key])
+}
+
+func removeHighAndLow(values []float64) []float64 {
+	sort.Float64s(values)
+	return values[1 : len(values)-1]
+}
+
+func avg(values []float64) float64 {
+	total := 0.0
+	for _, number := range values {
+		total = total + number
+	}
+	average := total / float64(len(values))
+	return average
+}