(WIP) Upgrade for React 16

[potench]

This is a work in progress.

Features

Update React Metrics to be compatible with React 16.

Problems

7 tests are currently failing, a few require redesign:

• Tests are dependant on react-router 2, this needs to be upgraded to react-router 4
• React 16 component error boundaries swallow errors, so intentionally testing for thrown errors in render() methods doesn't appear to work the same way.

[shimedh]

When will this available? Also will this library be making updates for future React versions?

[thongly]

We are also waiting on this PR in order to use the package with our application. Any updates would be appreciated.

[aplassen]

Any updates on this?

As of React 16.9 this will be logged out as a warning:

Warning: componentWillMount has been renamed, and is not recommended for use. See https://fb.me/react-unsafe-component-lifecycles for details.

* Move code from componentWillMount to componentDidMount (preferred in most cases) or the constructor.

Please update the following components: MetricsContainer