beautiful hints and "nice" radiobuttons
Merge branch 'master' of https://github.com/kontur-edu/uLearn

Conflicts:
	src/uLearn.Web/Controllers/CourseController.cs
	src/uLearn.Web/DataContexts/AnalyticsTableRepo.cs
	src/uLearn.Web/Scripts/_references.js
	src/uLearn.Web/Views/Course/Slide.cshtml