Changes in next

• Drop GHC 6.12 (and base-4.2.0.0) compatibility
• Fix Windows, GHCJS build
• Read instance for Fixed
• Applicative instances for strict and lazy ST
• Typeable instance for SampleVar
• Applicative and Alternative instances for ReadP and ReadPrec
• Typeable instance for KProxy
• Typeable instances for more data types in GHC.-prefixed modules
• Generic instances for Arity, Associativity, and Fixity from the GHC.Generics module
• Corrected the Generic instance for (:*:) to work around GHC bug #9830