Merge branch 'master' into 5.0

# Conflicts:
#	Sources/KingfisherManager.swift

Kingfisher.podspec

@@ -30,7 +30,7 @@ Pod::Spec.new do |s|
   s.ios.deployment_target = "8.0"
   s.tvos.deployment_target = "9.0"
   s.osx.deployment_target = "10.10"
-  s.watchos.deployment_target = "2.0"
+  s.watchos.deployment_target = "3.0"
 
   s.source       = { :git => "https://github.com/onevcat/Kingfisher.git", :tag => s.version }