Added installation instructions to README.md
Polishing installation instructions
Group competences hierarchically
Converted graph visualization to CoffeeScript
Refactoring graph view
Merge branch 'graph' into student

Conflicts:
	README.md
	app/controllers/curriculums_controller.rb
	app/views/curriculums/edit.html.erb
	app/views/curriculums/show.html.erb
Only show relevant skills in course graph view (in studyplan)