Vadymmarkov Malibu Versions Save

Add response decoding using Decodable https://github.com/vadymmarkov/Malibu/pull/113

Fix promise not being rejected when middleware fails https://github.com/vadymmarkov/Malibu/pull/112

• Update references https://github.com/vadymmarkov/Malibu/pull/108
• Use Travis instead of CircleCI https://github.com/vadymmarkov/Malibu/pull/110

Improve request modification: https://github.com/hyperoslo/Malibu/pull/107

• Remove ETag policy in favour of URLRequest.CachePolicy https://github.com/hyperoslo/Malibu/pull/105
• Rename Malibu.clearStorage() to Malibu.clearOfflineRequestStorage()

• Not including When in built framework #99
• Mock object can be constructed with JSON and a URL response #101

Remove validation of 204 responses in .validate() by @OscarApeland https://github.com/hyperoslo/Malibu/pull/90

Improve error handling https://github.com/hyperoslo/Malibu/pull/85

Tiny improvement to the request builder https://github.com/hyperoslo/Malibu/pull/83 by @OscarApeland