Enable Tim Pope's flatfoot plugin.

[Pi Delport]

The entry for this plugin was commented out, but i'd like to use it.

[marco-oweber]

ZyX should comment why he didn't enable it.

[ZyX_I]

I do not remember why exactly, guess I thought it is not published because is not stable enough and thus should not be enabled. See last commit, I uncommented “rake” and “flatfoot”, leaving “markdown” one commented with a comment explaining why.

[Pi Delport]

Cool, thanks. :)