Fixes rss generated dates to conform to RFC-3339.

The timezone was missing, since all are UTC, adds a Z.
Adds license page generated from static rst file. Refs #10.
Adds to footer hyperlink to forum content license. Refs #10.
Renders RSS entries in HTML. We are not from the past.
Merge branch 'pr_license_info' of git://github.com/gradha/nimforum into gradha-pr_license_info
Changed page title format.
Merge branch 'pr_html_rss' of git://github.com/gradha/nimforum into gradha-pr_html_rss