Made most small fixes for SPARK-849 except for table sort, task progress overlay
Sorts first column of env tables
Reverse sorts StageTable by submitted time
Pre-sorts stage/env tables, changes text/link of stage summaries
Overlays progress text on top of bar
Lightened color of progress bars
Update spark-standalone.md
Used saturated colors for progress bars
Merge pull request #787 from ash211/master

Update spark-standalone.md
Merge remote-tracking branch 'origin/pr/781'

Conflicts:
	core/src/main/resources/spark/ui/static/webui.css