Added shallow comparison checks to stateful components.

[n1k0]

Fixes #54.

@aduth, @magopian: could you please check this branch and see if it solves (or improves) the performance issue you're encountering? Thanks!

[n1k0]

First tests don't make me confident this is enough :/

[n1k0]

BAH. facebook/react#5677 (comment)

[n1k0]

Well, even if hackish as hell, last commit improves the situation a lot when filling large forms on the playground. Please guys provide feedback /cc @aduth @magopian

[aduth]

Apologies that I've not had the time to take a close look at this. Just took it for a spin, and I can confirm that it feels much more performant for reasonably fast form input. I must say, I'm a bit concerned about the impact that including Immutable.js will have on the bundle size, as it looks as though it may add upwards of 70kb minified prior to gzipping.

[n1k0]

I share your concerns. Though from my research, I couldn't find any better ways of performing nested object shallow comparison... If you have any idea how to implement shouldRender using vanilla js in an efficient fashion, I take it. Maybe just using deep-equal, deeper or equivalent may be just as fast but much less bloated?

[n1k0]

Side note, would be great to have some benchmark suite as a reference. I'll setup something.

[n1k0]

Achieving nearly the same perf boost using deeper, much better. Immutable would make sense if we wanted to use its structures everywhere, but it was definitely overkill here.