Project migration to the Swift 4.2

Add UIKit import for static compilation.

Preparing for the 4.0.0 release

Preparing for the 4.0.0.alpha.2 release

Merge pull request mac-cain13#21 from Kuniwak/avoid-dirty-submodule

Avoid dirty submodules for Carthage users

Preparing for the 3.0.2 release

Preparing for the 3.0.1 release

Preparing for the 3.0.0 release

Preparing for the 3.0.0.beta.1 release

Preparing for the 2.3.0 release