added <supportedLanguages> tag in Adobe Air descriptor

iTunes lists around 15 different languages when user does not provide this <supportedLanguages> tag. Now it defaults to "en", and is optional configurable in the _flambe.yaml_ file ("supported_languages" setting)

Reference: 
http://help.adobe.com/en_US/air/build/WSfffb011ac560372f2fea1812938a6e463-8000.html#WS06ac295d95cf5a5c-4601cdc2134337a7308-8000