Add support for help hover tip on widgets
Re-add label mug help tip and fix label text.

Got lost during major refactoring (4c391f92).
Add missing library to install dependencies
Merge branch 'develop' into develop-staging

Conflicts:
	dist/vellum.min.js
	src/js/formdesigner.javarosa.js
	src/js/model.js
	src/js/widgets.js
	src/templates/main.html