Migrate codebase to React 16-compatible lifecycles

[Rendez]

1. Uses Lifecycles from 16.3 to guarantee future compatibility.
2. History objects are only created if there's an existing DOM in the runtime: this gives implementors the chance to skip initializing history on runtimes without DOM polyfilling/support, e.g.: a running instance Node.js without js-dom.

Depends on #28

[gitgrimbo]

Hi, will this be merged?