Fixed loading of images via url

The problem: Using urls for the icon and logo images will fail. It will load at all of them but one. It finalises the manifest by calling doneWithImages() before the file has been loaded into the manifest.

The fix: listen for the file close event and then call doneWithImages if needs be. The sha hash generation takes time which caused the problem, this fixes that.

Also I added passkey.pem as this is needed to sign the pass now.
I also removed the signature check test as it will only ever pass on osx which is not ideal.

All tests pass.