Allow topics to be selected via topic tree on graph pages.
Merge branch 'IDOC_coach_reports' of git://github.com/rtibbles/ka-lite into IDOC_coach_reports

Conflicts:
	kalite/templates/coachreports/base_google_visualization.html
Plot scatterplots for specific topics selected from the tree.
Merge branch 'IDOC_coach_reports' of git://github.com/jamalex/ka-lite into IDOC_coach_reports