Timestamp improvements

Implements Issue #40 .
Added the moment.min.js file to the appropriate locations. Updated the
index.html to include some divs for the info to go.

Tests all passed (Identity and Pre Key Creation took a while though).

Updated some CSS to make things look a bit nicer.

Localization added via MomentJS (kept the filename as moment.min.js to keep the name short). Defaults to English, easy to switch with a language code such as 'fr' or 'de'.

EDIT:

The moment.min.js file in js-deps is Not a Contribution (as I did not write it). It is licensed under the MIT license copyright Tim Wood, Iskren Chernev, Moment.js contributors The license info is also contained in the actual file as a comment.

Link to License: https://github.com/moment/moment/blob/develop/LICENSE
Fair enough, I wasn't sure where it should go but wanted it explicitly stated. Would it go in a new .js file or in options.js?

Looks like it would be easy to grab the browser's locale setting and use that as the default (from here http://stackoverflow.com/questions/25725882/locale-detection-with-moment-js ). 

Then on the options page we could give the option to explicitly set the locale.