Support non-web platforms

[benwiley4000]

The use of the DOM api to polyfill fragment means this isn't usable on other platforms.

[wishfoundry]

can't you just replace this with something like:

function Fragment(props) {
    return props.children;
}

[benwiley4000]

@wishfoundry I might be missing some context, which you could explain, but I don't think that would work for a couple of reasons:

1. Array-as-render-result requires keys on each list item whereas Fragment does not.
2. Array-as-render-result isn't supported prior to React 16. A goal of this lib is to support React 15.