tweak handling of slow/missing upstream

our fetch and render timeouts were both 20s,
causing the 'finish early' event to fire immediately before 
the upstream timeout turns it into a 400.

This moves the upstream connection timeout to 10s,
meaning unavailable servers will hit 400 instead of 'working...'.

I also removed the 'Fetched...' timing diagnostic message when the fetch fails.
minor text editing

on FAQ and error pages
second FAQ pass

use Notebook Viewer where possible
compacting footer view #230
GitHub client shouldn't authenticate twice
Merge pull request #248 from jvns/dont-authenticate-twice

GitHub client shouldn't authenticate twice
fixing up whitespace and footer tag to add a little padding at bottom of page
Merge pull request #246 from adamw523/footer

compacting footer view #230
Merge pull request #243 from minrk/slow-fetch

tweak handling of slow/missing upstream
Merge pull request #244 from minrk/copy-edit

minor text editing
more redable dates
Merge pull request #251 from Carreau/momentjs

more redable dates
Merge branch 'master' of github.com:ipython/nbviewer

Conflicts:
	nbviewer/app.py