Don't leak as a global

[orls]

Quay currently supports loading as an AMD module, but because the code is all in top-level script scope, it's still leaking a global Quay object. You can see this by loading it through requireJS then checking window.Quay.

If you're serious about supporting module loading, you might want to looking into wrapping the whole thing in an IIFE, then doing the define sniff inside that -- for example, following the UMD guidelines