Simplify URLs that start with 'http://'

Since 'http://' is the default protocol for the Web, we can avoid
showing it in a few places. This improves the signal-to-noise ratio in
the app, and makes it more obvious when a URL is using 'https://'.

This is also consistent with how Chrome shows URLs that begin with
'http://', so people should be more or less familiar with this technique
by now.

Change-Id: I03fa5180ce57a8228c2988b9e922fd52b64019de
Shorten "Website URL" to "URL", add <abbr>

The copy "Website URL" seems a bit unnecessary to me, so I am
simplifying it to just "URL". At the same time I added an <abbr> tag
with a class of .initialism, which is a feature of bootstrap that makes
the text slightly smaller. This also improves the consistency of the
copy in the app.

Change-Id: I2cd5be8f0d72aa45ae4588444ddcc6358af33060
Drop colons from snapshot metadata table

The fact that these elements are <th>'s is enough of a visual indicator
of their purpose. Dropping the colons to simplify and reduce noise.

Change-Id: Idc69bc70fb9af94dd7fc8dc8c1e2d5d43f9a0f75