allow updating by switching to a branch
Merge branch 'release-0.11' of github.com:learningequality/ka-lite into update_to_branch

Conflicts:
	kalite/management/commands/update.py
Removing merge marker
Merge branch 'release-0.11' into update_to_branch
Merge pull request #1041 from bcipolli/update_to_branch

allow updating by switching to a branch