B2SBackglassServerRegisterApp should unblock files while registering

[JockeJarre]

The code in C# looks like this

public class FileUnblocker {
[DllImport("kernel32", CharSet = CharSet.Unicode, SetLastError = true)]
[return: MarshalAs(UnmanagedType.Bool)]
private static extern bool DeleteFile(string name);

public bool Unblock(string fileName) {
    return DeleteFile(fileName + ":Zone.Identifier");
}

}