openUrl function for all platform but on windows RT empty function
Added method for converting from std::string to Platform::String.
Windows Phone 8 can now open URLs.
Added tests for opening a URL.
Tests for Mac/iOS android Linux & Windows
Merge pull request #8136 from andyque/moveWinEditBox

remove Win32InputBox.cpp/.h, move them to UIEditBoxImpl-win32.cpp
Merge pull request #7975 from newnon/v3_openUrl

openUrl function for all platform but on windows RT empty function