A lot of changes: ajax data, sidebar li links, query fixes, marks rename
Merge branch 'master' of https://github.com/kontur-edu/uLearn

Conflicts:
	src/uLearn.Web/Content/ulearn.css
	src/uLearn.Web/Controllers/AnalyticsController.cs
	src/uLearn.Web/Scripts/_references.js
	src/uLearn.Web/Views/Analytics/PersonalStatistics.cshtml
	src/uLearn.Web/Views/Course/Slide.cshtml
	src/uLearn.Web/Views/Course/_RatesBar.cshtml
Rates fixes git add -Agit add -A