guideid: parse from url

and use an actual http request instead of the fake data.
Show loading spinner before the guide is rendered.

I didn't want to bother detecting image loads, so I just threw in a
delay.

the idea is that the HTML and the CSS for the loading spinner are in
the page itself so it should show *very* quickly.
Show 'Guide not found' error

Instead of a blank screen.
Merge pull request #1 from danielbeardsley/loading-spinner

Parse guideid from url and load via HTTP