fix inputEqual
add iterateeInputArbitrary
iteratee Input tests
remove Monoid[Input] and MonadPlus[Input]. because does not satisfy laws
fix enumIterator
add enumIterator test
fixed enumIterator memory leak
simplified enumIterator
Merge pull request #461

fix #390 iteratee Input instances
Merge pull request #564 from anovstrup/enumIterator

Fix for issue #553