Fix building with ghc-7.4
Add an unversioned package doc redirect

That is /package/foo/docs/blah.html -> /package/foo-1.0/docs/blah.html
Using a temp redirect to whatever is the latest version.
Fixes issue #61
Add checking for doc tarball uploads

This does not fix issue #56 however it does help because it will give
people decent feedback when the upload the doc tarball, rather than
when they try to read it later!
Fix rendering of html error responses

Was accidentlly including the html doctype again
Use ugly html rendering; faster and less bandwidth