[[ Bug 13827 ]] Use UTF-8 strings when building iOS externals

I'm sure that I have updated lcidl to allow the user to use UTF8-encoded string, as well as libexternalv0. But I don't think that libexternalv1 (which is used by revmobile) has been updated. 
The fix works since the first parameter passed to revIphoneLaunchApp is definitely a UTF-8 encoded string, provided the change I've made to revdeploylibraryios.livecodescript.
That said, the best should probably be updating libexternalv1 (currently, external.h doesn't have the new enumeration such as kMCOptionAsUTF8String).