Make templates for branding components

Saves having lots of text in the Python module
Add a note about user photos
Oops - I broke all the branding URLs, fixing
Handling non-existent templates more politely
Loosening restrictions on resource names
Moving COMPONENTS into branding/utils.py, and renaming
Import tidy
DRYer branding
Re-formatting to make the code easier to read
Clarifying help text
Add notes on the Apple logos, and use <small>
Improving wording
Moving BrandingInformation into kanisa.utils.branding
Fixes #73 - add default image for event contacts

This only affects the management interface
Don't crop logos
Fix weird display if event contacts don't have registered emails
Add a link in the header to the management area for permissioned users
Add a note about {% load url from future %}
Removing load url from future, the future is here
Narrow path to 1.0

Ensuring 1.0 only has things that are absolutely needed
(i.e. ensure we're in at least as good a position as we are
with Kaleo).

Also, add a version 0.8, where we tidy up external
dependencies.