Implement the `open` function

[patw0929]

Try and test on different devices again and again made me feel a little dizzy... anyway, it should be refactor in better way. 😅

• Implement the open function:

  • Removed the display: none style of iframe, because seems that causes the iframe not working.
  • Android's case is much more complicated, I am not sure if it can work on all the Android Browsers.
    • When user set the packageName:
      • Chrome:
        • Not installed app: Cannot open the app (by scheme) on Chrome Android definitely, so it will open the app's download page on Google Play.
        • Installed: Just open the app by scheme.
      • Other browsers:
        • Try the iframe approach. It will resolve with false if it cannot be opened.
    • Without packageName:
      • Chrome:
        • Try to open it, and also resolve with false if cannot be opened (detect in Chrome way).
      • Other browsers:
        • Try the iframe approach. It will resolve with false if it cannot be opened.
  • Other devices:
    • Not implement in this pull request.

• reference:

  • https://stackoverflow.com/questions/7231085/how-to-fall-back-to-marketplace-when-android-custom-url-scheme-not-handled
  • http://qiita.com/kzhrk/items/842c046265e4e50914c6#androidchrome
  • https://blog.patw.me/archives/1069/js-app-url-scheme-open-workaround/

[yutin1987]

Sorry, had conflicts.