Add Bootstrap to app

We include Bootstrap in the Gemfile and then include the CSS and JS
files for the asset pipeline.
Test for basic layout with Bootstrap

Some simple tests that check that we're trying to use some simple
features from Bootstrap to layout our site nicely:  the navbar and the
container.
Merge commit '281553c05b435e1607f998fd201921ae992f17c7' of http://github.com/geisler/worship_together

Conflicts:
	Gemfile
	app/assets/stylesheets/application.css.scss