fixed broken transform example

the transform example (which capitalizes an input string) didn't work for me (using `integration-0.3.1` and `node-0.8.17`). i believe this is because the translator, `String.prototype.toUpperCase`, is an instance method, and the translator is [invoked without a `this`-binding](https://github.com/s2js/integration/commit/9068264d57a8cbce2df5cc59ca60471c591699d6#L20R562). maybe it would be interesting to bind translator invocations to the message (or even the bus / routing context), and allow it to access the payload, headers, and other properties/methods via `this`?