fixes on check plugin
Merge branch 'master' of github.com:ralsina/nikola
fix #510
support schema-relative URLs in checker
Basic template dependency detection for Jinja (Issue #511)
Persist and re-use last RSS feed build date.
Hack to repair the "guid" damage, that might flood the planet.
Added support for tag clouds to site theme.
Use absolute URLs for relative URLs that go upwards.
Preserve mode when using inplace filters that use a temporary file.
Follow the 302 redirect error that disqus.com is giving.