[TIMOB-13982] iOS: URL Scheme is invalid if it contains umlauts or begins with a digit

The current URL Scheme is based on the app-name. Is this used internally in the rest of the TiSDK or just to give all apps an option to open the app via an URL? The problem is, if it contains umlauts (ä,ö,ü etc.) or begins with a digit, it's invalid. You can't submit your app to the iOS App Store. If the URL-Scheme isn't used somewhere internally, then i think you could remove this part and leave the option up to the developer, if he wants is app to be opened via an URL by extending the part in tiapp.xml. If it is used internally, both parts (generating, and creating links / listeners internally) should be patched to transform the appname to a valid urlscheme. This Regular Expression should match all invalid characters:

[\d\s\W]

another thing on replacing the characters with maybe nothing is to replace umlauts to the corresponding replacements (ö => oe, ü => ue etc)