Changed from the partial rename to Data.MissingHStr

This is necessary because the Data.String name is already taken by a module in base, and this clash causes problems for any other programs importing Data.String - like HSH.

Partial because there is an import which may or may not be needed, I am unsure.

Remove 3 imports, and the splitComma function; they are neither exported nor used in anything that is exported, and there's no indication they might be needed in the future.

requires one slightly less than pleasent hack because Patternsignatures
is not recognised by ghc-6.6 or the cabal that comes with 6.8.1, only
by the latest cabal that comes with 6.8.2.
Drop GHC-Options: -O2 as Cabal adds optimizations by default but also
lets the user configure with --disable-optimization, so there is no longer
any need to force optimisations on all the time and it prevents users
configuring without optimisations for quick builds.