remove the dependency on the `either` instance as a mean of improving…

… tree shaking

make Decoder module more tree shaking friendly and remove applicative…

… instance

add `TypeOf` operator to Codec, Encoder, Eq and Guard, closes gcanti#462

collect all errors while decoding, closes gcanti#449

version 2.2.0

fix regression in v2.1.2

remove useless hasOwnProperty calls, closes gcanti#423

fix `record` domain handling, closes gcanti#391

version 2.1.0

whitelist window in UnknownRecord, fix gcanti#413