Added 'Event Guides' button and general style improvements.

First half of ticket #882847 mockup complete.
Added initial party-banner bar.

Mostly resolves ticket #882847 (https://bugzilla.mozilla.org/show_bug.cgi?id=882847), with the following remaining issues:
  * unseemly white gap under party-banner
  * map-canvas needs to take 100% of the remainder of the page (no scrollbars).