fixed call to bundle file in example

[silverlight513]

I'd been trying to get HMR working with the package and decided to clone the repo so I can see how the example works. Kept getting 404's when it was calling client.js. Looked into the webpack config and noticed it was creating a file called bundle.js.

[coveralls]

Coverage remained the same at 80.808% when pulling 9890dcc on silverlight513:example-fix into a257b08 on glenjamin:master.

[glenjamin]

Good spot, thanks