Whitespace tidy
Add a constant for the maximum length of a link title
Ensure the root links can be navigated to

Also, slightly loosen the restriction on nav element
description lengths.
Ensure long descriptions for navigation links are trimmed
Move download link rendering to a template
More obvious download links
Fix display of inline image management interface for Bootstrap 3
Fix layout of speakers in the management interface for Bootstrap 3
Add a note about service planning
Tidy up templates for event contact and banner thumbnails

These now work with Bootstrap 3.

I've also removed the pop-over modal for the banner, since
it was liable to get out of sync with the display on the
home page (also, banners will go away soon, per TODO.md).
This is now done
Organise 1.1 TODOs

These have got a bit out of hand, as 1.1 has become a
dumping ground for "not needed before initial release".
Don't think we'll do Twilio integration
Shuffling a few things around to 1.2