Some tweaks to the appearance

The div with classes "box warning" was replaced with a button or simply a
text.
Add 'nofollow' to X-Robots-Tag header, remove debugging output
Bump version
Don't show messages on AJAX requests

Django's message framework deletes the messages after being shown once,
this is nice but doesn't work on AJAX requests. For this, we set a
custom header that supresses the messages. Fixes #5
Small improvements, use bootstrap's buttons
Merge pull request #23 from rolandgeider/master@github

Merge