Add tarballs to "clean"-target
Tweak VERSION to avoid leading 0s

The release version has to be in normal form (i.e. `13.6` instead of
`13.06`) as otherwise ELPA-like repositories such as Marmalade
misbehave.
Convert coding of `haskell-{doc,mode}.el` to UTF8

These two are the only elisp files left still using iso-8859-1 for
non-ASCII characters, and might have been the cause for issues such
as #157