Update Podspec

Author: Gleb Radchenko

DNWebSocket.podspec

@@ -19,8 +19,8 @@ Pod::Spec.new do |s|
   s.tvos.deployment_target = '9.0'
   s.watchos.deployment_target = '2.0'
 
-  s.source_files = 'Sources/**'
+  s.source_files = 'Sources/**/*.swift'
   s.pod_target_xcconfig = {'SWIFT_INCLUDE_PATHS' => '$(PODS_TARGET_SRCROOT)/Sources/CZLib/** $(PODS_TARGET_SRCROOT)/Sources/CommonCrypto/**'}
-  s.preserve_path = 'CZLib/module.modulemap', 'CommonCrypto/module.modulemap'
+  s.preserve_path = 'Sources/CZLib/**', 'Sources/CommonCrypto/**'
 
 end