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

Ah! Okay - I see you are textEncoding the data in the LC script :)

It would probably be best to roll the tweaks from externalv1.cpp constants into libexternalv1/external.h header and then use the appropriate accessor (AsUTF8CString) in the revIPhone external rather than textEncode in LC - saves confusion at a later date.