Some more fixes in redirects and code

* Redirect fiu-vro to vro.
* Redirect roa-rup to rup.
* Redirect zh-yue to yue.
* Remove pru. Only prg is the right code for Prussian.
  pru is a code of a language in Indonesia, about which
  there's very little information, so it's better to remove it.
Merge pull request #65 from amire80/more-aliases-and-fixes

Some more fixes in redirects and codes