ReSwift/ReSwift breaking changes

Drop support for Swift 3.2, 4.0, and 4.1. (#418) - @DivineDominion

Drop support for iOS 8 (#447) - @DominicSchiller-IBM-CIC **API Changes:**

Add capability to mutate `Middleware` after store creation. (#427) - @mjarvis **Other:**

Removes the ability to directly set `state` by making it `private(set)`. This prevents users from bypassing reducers and middleware. All mutation of the state must occur through the normal `Action` & `Reducer` methods.

The existence of `StandardAction` and `StandardActionConvertible` is somewhat confusing to new users, and does not have a direct use case within the core ReSwift library. Therefore, it has been moved to [ReSwift-Recorder](https://github.com/ReSwift/ReSwift-Recorder) where it belongs.

If you're using `StandardAction` in your project without `ReSwift-Recorder`, you can copy the old implementation into your project as a middle ground while you migrate away from its usage.

Make Store's state setter private (#354) - @mokagio

Remove `StandardAction` and `StandardActionConvertible` (#270) - @mjarvis

The subscription API provides basic operators, such as `skipRepeats` (skip calls to `newState` unless state value changed) and `select` (sub-select a state).

Introduced a new Subscription API (#203) - @Ben-G, @mjarvis, @DivineDominion

This is a breaking API change that requires migrating existing subscriptions that sub-select a portion of a store's state:

Subselecting state in 3.0.0: ```swift store.subscribe(subscriber) { ($0.testValue, $0.otherState?.name) } ```

Subselecting state in 4.0.0: ```swift store.subscribe(subscriber) { $0.select { ($0.testValue, $0.otherState?.name) } } ```

Dropped support for Swift 2.2 and lower (#157) - @Ben-G **API Changes:**

Mark `Store` as `open`, this reverts a previously accidental breaking API Change (#157) - @Ben-G **Other**:

Update to Swift 3.0.1 - @Cristiam, @Ben-G

Documentation changes - @vkotovv

Significant Improvements to Serialization Code for `StandardAction` (relevant for recording tools) - @okla

Swift 2.3 Updates - @agentk

Documentation Updates & Fixes - @okla, @gregpardo, @tomj, @askielboe, @mitsuse, @esttorhe, @RyanCCollins, @thomaspaulmann, @jlampa