Prim.hs: add Eq instances to MPDError and ACKType.
Prim.hs: add Eq instances to MPDError and ACKType.

darcs-hash:20071014104951-87dc9-8a93b687362644ae78343cbd67e8d73089398e63.gz

sol/libmpd-haskell,beni55/libmpd-haskell