fix(DevTools, LogMonitor): prevent LogMonitor to render once as visible state

[nikgraf]

I noticed that LogMonitor is rendered once, because isVisible is set to true in the initial state.
see https://github.com/gaearon/redux-devtools/blob/master/src/devTools.js#L89

In the LogMonitor the isVisible state was updated, but that will only affect the second render cycle. This is an issue in case you try to create a universal/isomorphic application with the same template.

I propose to fix it by updating the props optimistically. As an alternative we could do this case inside the LogMonitor. Let me know what you think 😄

[gaearon]

Thanks for the PR! I'm closing because the way monitors currently manage their state isn't composable.
Please track the solution to this in next branch: #132 (comment)