Allow voting on community examples

[richierocks]

Sorting the community example by most recent means that good submissions eventually get buried. for example, on the ?mean page, there are dozens of examples that are blank, badly formatted, or don't contribute anything useful. The most informative examples are older, but hard to find amongst the spam.

[ben-brooker]

Closing this issue as the client-side of this application is now in the Rdocumentation2.0 repo. :)