Don't output microseconds in datetime attribute of <time> html tag
Merge branch 'develop' of ssh://github.com/liqd/adhocracy into develop
Add optional append_slash keyword argument to base_url function

Enabling append_slash makes the resulting URL end with a slash.
Fix comment editing and tag autocompletion with relative_urls

Addendum to e74eaf6b0f0bda02dd3a69ac2e0065c6071c6503
Fix comment editing after base_url change

Addendum to ad4c95357faeea8c96f28346fbde2f808162c290
Only revert to not-newest comment revision