Add CFNetwork as linked framework

Kingfisher.podspec

@@ -31,6 +31,6 @@ Pod::Spec.new do |s|
   s.source       = { :git => "https://github.com/onevcat/Kingfisher.git", :tag => s.version }
   s.source_files  = "Kingfisher/*.swift"
   s.requires_arc = true
-  s.weak_framework = 'WatchKit'
+  s.framework = "CFNetwork"
 
 end

Kingfisher.xcodeproj/project.pbxproj

@@ -8,6 +8,7 @@
 
 /* Begin PBXBuildFile section */
 		0D9C68098E20AB4F19D7C313 /* libPods-KingfisherTests.a in Frameworks */ = {isa = PBXBuildFile; fileRef = A9E621E297FEFAD35D39C34E /* libPods-KingfisherTests.a */; };
+		4B164AD01B8D556900768EC6 /* CFNetwork.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = 4B164ACE1B8D554200768EC6 /* CFNetwork.framework */; };
 		4B2C4DF81B7D7ACD000912CA /* Resource.swift in Sources */ = {isa = PBXBuildFile; fileRef = 4B2C4DF71B7D7ACD000912CA /* Resource.swift */; };
 		4B412CA51AE8A2F9008D530A /* KingfisherOptionsInfo.swift in Sources */ = {isa = PBXBuildFile; fileRef = 4B412CA41AE8A2F9008D530A /* KingfisherOptionsInfo.swift */; };
 		4B6D4F651AE0A46D0084D15B /* UIImageViewExtensionTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = 4B6D4F641AE0A46D0084D15B /* UIImageViewExtensionTests.swift */; };
@@ -85,6 +86,7 @@
 /* End PBXCopyFilesBuildPhase section */
 
 /* Begin PBXFileReference section */
+		4B164ACE1B8D554200768EC6 /* CFNetwork.framework */ = {isa = PBXFileReference; lastKnownFileType = wrapper.framework; name = CFNetwork.framework; path = System/Library/Frameworks/CFNetwork.framework; sourceTree = SDKROOT; };
 		4B2C4DF71B7D7ACD000912CA /* Resource.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = Resource.swift; sourceTree = "<group>"; };
 		4B3E714D1B01FEB200F5AAED /* WatchKit.framework */ = {isa = PBXFileReference; lastKnownFileType = wrapper.framework; name = WatchKit.framework; path = System/Library/Frameworks/WatchKit.framework; sourceTree = SDKROOT; };
 		4B412CA41AE8A2F9008D530A /* KingfisherOptionsInfo.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = KingfisherOptionsInfo.swift; sourceTree = "<group>"; };
@@ -134,6 +136,7 @@
 			isa = PBXFrameworksBuildPhase;
 			buildActionMask = 2147483647;
 			files = (
+				4B164AD01B8D556900768EC6 /* CFNetwork.framework in Frameworks */,
 			);
 			runOnlyForDeploymentPostprocessing = 0;
 		};
@@ -255,6 +258,7 @@
 		EA99D30544BD22799F7A5367 /* Frameworks */ = {
 			isa = PBXGroup;
 			children = (
+				4B164ACE1B8D554200768EC6 /* CFNetwork.framework */,
 				4B3E714D1B01FEB200F5AAED /* WatchKit.framework */,
 				A9E621E297FEFAD35D39C34E /* libPods-KingfisherTests.a */,
 			);