update internetgateway1 example to build on go1.4

the Service field on the ServiceClient is already *goupnp.Service, so taking the address makes it a **goupnp.Service which no longer will dereference to call methods on type *goupnp.Service like String and RequestSCDP.
Merge pull request #3 from zeebo/patch-1

update internetgateway1 example to build on go1.4