MPD.Processing (sepBy): span (not . p) is break p
MPD.Handle: de-lint
MPD.Remote: de-lint
Explicit export lists
MPD.Handle: conditionally export parseVersion for testing
MPD.Interact: fix usage example for keepAlive

`ping` swallows all exceptions; throw an exception to make `keepAlive`
retry the computation.
Merge branches 'hlint', 'explicit-export' and 'fix-keepAlive-example'