Changelog for leveldb-haskell-0.4.0

[0.4.0]: * New streaming interface (experimental) [0.3.1]: * Deprecate `mapIter`, `iterItems`, `iterKeys`, `iterValues` [0.3.0]: * ResourceT is no longer compulsory [0.2.0]: * requires LevelDB v1.7 * support for filter policy (LevelDB v1.5), either custom or using the built-in bloom filter implementation * write batch values no longer require a `memcpy` to be early-finalizer-safe (introduced in 0.1.1) [0.1.0]: * memory (foreign pointers) is managed through [ResourceT](http://hackage.haskell.org/package/resourcet). Note that this requires to lift monadic actions inside the `MonadResource` monad, see the examples. * links against shared library (LevelDB v1.3 or higher) * LevelDB 1.3 API fully supported (including custom comparators, excluding custom environments) [0.0.x]: * experimental releases