use appid of official VLC app in example

The appid of the official VLC app is `org.videolan.vlc-ios`. See `CFBundleIdentifier` here:
http://git.videolan.org/?p=vlc-ports/ios.git;a=blob;f=AspenProject/VLC+for+iOS-Info.plist;h=2b07bb8037c16df6b488313aa98beb406ed099b3;hb=HEAD#l53