adds Q to exports for browserify

From pull request:

NodeJS: adds Q to exports for browserify

When using the Node.js libs in the browser (via browser.js) Q isn't
exposed the same way as it is in a Node environment. If I try to call
an API function without a callback function it will throw the following
exception: TypeError: Cannot read property 'defer' of undefined. This
just adds Q to the exports in browser.js to make consuming the libs
more consistent with how we do in an actual Node environment.