Autoretry Failed to add url

[Sypher]

For some reason, fetching some items from the RSS failed. Probably because there was a temporary failure on the site.
Is it possible to automaticly re-try those failed URL's?

From the looks of it, when the URL is marked as "failed", the RSS force download/autochecker doesn't re-check it.

Also, a reason of why it failed might be nice to have as well.

[shypike]

Already in 0.5.1RC2