Support Xcode9.3 and Update Swift to 4.1

• Support Xcode9.3 and Update Swift @yutailang0119
  • Support Xcode 9.3
  • Update Swift version to 4.1
  • Support Safe Area of ZenWebViewController
• Support universal devices of DemeApp @yutailang0119
• Bump version of podspec @yutailang0119