Add bootstrap 'container'.

Anything within the div with class container gets some default styling and spacing from bootstrap.
If you want the header/footer to have this spacing too, then just remove this div and put class="container" on the <body> instead.
Fixed typo in footer.
Formatting.
Hide alert and notice if nil
Initial styling for single group
Click overview of group to go to its details.

Needs better styling.
Remove link styling for group overviews.
Add button to see details.

Note that while there is a clickable button, the entire div is also clickable. I wanted the entire div to be clickable to be a bigger target, but I also wanted users to be able to realize that they can click on it.  Suggestions welcome.
Implement button the Rails way
Merge pull request #8 from anthonye2007/list-groups-view

Basic group overview