Notifications firing on iCloud sync

#36: Notifications will now be posted after an iCloud sync has occurred (thanks to @twostraws)

Swift 5.0 Support

As of Zephyr v3.3.0, all future changes on master will be done in Xcode 10.2 using Swift 5.0.

For those using Swift v4.2, please check out the swift4.2 branch or version 3.2.0 - both point to the same commit hash.

Swift 4.2 Support

As of Zephyr v3.2.0, all future changes on master will be done in Xcode 10 using Swift 4.2.

For those using Swift v4.1.0, please check out the swift4.1 branch or version 3.1.2 - both point to the same commit hash.

Minor optimizations

• Minor swift optimizations
• Improved documentation.

Synchronized `monitoredKeys`

• #30: monitoresKeys are now synchronized. (Thanks to @krzyzanowskim)

Custom UserDefaults synchronization and Swift 4.1

• Adds the ability to sync non-standard UserDefaults objects.
  • Thanks to @albertwujj in #28
• Adds Swift 4.1 Compatibility

Modernized Podspec file and Removed watchOS Support

• Updated Podspec file.
• Removed .swift-version file, as it's been deprecated.
• Removed watchOS support since there are a few insurmountable issue (and because it seems no one was using or requesting this support).

Fixes Background Sync Issue (Swift 4 Bug)

• Fixes #25. When converting to the codebase to Swift 4, the @objcMembers keyword was missing, so the KVO method was never being hit. This has been addressed.

Support for Swift 4 / iOS 11 / Xcode 9

Zephyr v3.0.0 adds support for Swift 4 / iOS 11 / Xcode 9. Only minor changes were made under-the-hood.

Moving forward, only support for the Swift 4 codebase (on master) will be maintained.

Swift Version	Branch Name	Will Continue to Receive Updates?
4.0	master	Yes
3.2	swift3.2	No
3.1	swift3.1	No

Fixed Carthage Support

I broke Carthage support in v2.2.0. Fixed it in v2.2.3.