4.0.0

• 🍔 Swift 4.2 #54
• 🍔 Adds .alphaComponent, .hueComponent, .saturationComponent and .brightnessComponent to UIColor #51
• 🐞 Fixes crashes related to force-unwrapping. #58
• 🐞 Fixes bug related to completion being called in the wrong queue. #60
• 🧹 Reduces deployment target to iOS 8.0. #56
• 🧹 Perform latest migrations on the Xcode project. #59
• 🧹 Restructures the project. #59
• 🧹 Fixes warnings about deprecated functions. #61

Thanks to @jiangpengyun, @andy1247008998, @boherna, @pushchris, @gmlwhdtjd and @Injazz for marking this the best version to date!