Sweeten GET operations by returning NULL instead of throwing.

[chadxz]

Typically when you issue a GET to grab a specific instance of something, as a developer, you want either the thing, or null, so you can do something like if(thing) doSomething(); afterwards.

Today if you get back a 404 from the server on an operation like GET /applications/{applicationName}, it will cause the promise to throw. Ideally this would instead resolve the promise with null.