New method for sorting tags: articles count.
Moved archives to /blog so people find something when hit this path. Set Pelican's content source paths. Add Jinja extensions as they are undocumented on Pelican, just in case. Add category to post signature. Change 'read more' button. Better tags output on index. Add semantics on index paginator and sidebar.
Conflict resolution on Elcio's Jinja filter patch.