reduce repetition, simplify
separate contact recipients from admins
Merge branch 'simplify-makefile'

Conflicts:
	Makefile
disable twitter when not configured
update js libs
fixes django-pipeline problems
create a proper test of collecstatic
fix add activity layout on lesson page
fix video aspect on admin, fixes #494 login prompt
Merge branch 'master' into site-tour

Conflicts:
	themes/default/templates/course.html