Retrieve version from MANIFEST, for PlayBook AIR apps

//-----------------------------------
// Retrieve application version from metadata.
//
static public function getAppVersion():String {
    // The alternative to this mess is to use File.userDirectory, but I don't consider
    // that guaranteed to always point to the parent of app/META-INF
    var manifest:File = new File(File.applicationDirectory.nativePath).resolvePath('../META-INF/MANIFEST.MF');

    var file:FileStream = new FileStream();
    file.open(manifest, FileMode.READ);
    var text:String = file.readUTFBytes(Math.min(manifest.size, 1000));
    return /Application-Version: (.+)/i.exec(text)[1];
}