Added function to copy provided assets (*.gwc) files to ios8 documents folder on App start

I have seen that there is a sample .gwc file in the "asset" folder. It was also marked as Build Action -> Content, to copy it to the application bundle. But in ios8 it has to be in application documents folder.

I added a small function that will copy all *.gwc files from resources bundle to the documents folder if they not exists there.