3 days spent redoing the Android autobuilder! The new version of
yesod-routes generates TH splices that break the EvilSplicer. So after
updating everything to new versions for the Nth time, I instead went back
to older versions. The autobuilder now uses Debian jessie, instead of
wheezy. And all haskell packages are pinned to use the same version
as in jessie, rather than the newest versions. Since jessie is quite near
to being frozen, this should make the autobuilder much less prone to
getting broken by new versions of haskell packages that need patches for
Android.

I happened to stumble over <http://hackage.haskell.org/package/setenv>
while doing that. This supports setting and unsetting environment variables
on Windows, which I had not known a way to do from Haskell. Cleaned up
several ugly corners of the Windows port using it.
