Show troubleshooting tab if React cannot be found

[appsforartists]

Right now, if RDT doesn't think your page is Reactful, it will not draw the tab at all.

(Moreover, the best-practice of using webpack/browserify to load React will fail RDT's "is this page Reactful?" test, so the React tab will never draw.)

I propose that the React tab is always present. If RDT doesn't think the page is Reactful, it will say something to the effect of:

Sorry, but we couldn't find an instance of React on this page.

Make sure it has been exposed as window.React, then reload.
^{If you are sure it has been exposed at window.React and you are still seeing this message, [Click here] and we'll double-check.}

[Click here] will try to load RDT again without reloading the page (in case there's a race condition that's preventing RDT from seeing React).

[appsforartists]

It also seems like the handoff between React and RDT should be smarter than if (window.React). If, for instance, React.renderComponent attempted to connect to the dev tools, you should avoid most cases where the dev tools are installed but don't render. Those that do occur would be easy to solve (call renderComponent again).

[sophiebits]

As of React 0.12, React does connect to the dev tools and shouldn't require exporting window.React. (Looks like the README should be updated…)

[appsforartists]

Upgrading to 0.12 fixed this for me.