[WIP] clear radium state for unmounted components

[stefvhuynh]

Initial attempt to resolve #524.

1. Keep track of children keys when going through them recursively in resolve-styles.js
2. Check these keys against the state in enhancer.js
3. Remove the keys in the state that correspond with unmounted components in enhancer.js

There is still a lot of cleanup to do, but I'm looking for opinions on the approach.

[stefvhuynh]

@ryan-roemer, @ianobermiller, this is an initial attempt at resolving this issue. Can I get thoughts on the approach?

[coveralls]

Coverage decreased (-1.0%) to 93.056% when pulling 25786b9 on hover-state into 2c4ae5e on master.

[coveralls]

Coverage decreased (-1.0%) to 93.056% when pulling 25786b9 on hover-state into 2c4ae5e on master.

[alexlande]

General approach looks solid. I'm a little nervous about the check in componentDidUpdate because it could be called extremely frequently in some cases (like if you're doing animations), but I can't think of a better way to handle it.

[stefvhuynh]

@alexlande, another possible approach would be to expose setState on radium as suggested by some people in the issue. though, it seems like it would make sense to clear style states if a component is removed anyway.

[alexlande]

@stefvhuynh Yeah, it doesn't feel like something that users should have to handle, if we can do it automatically.

[stefvhuynh]

@alexlande, alright, i'll clean this up then.

[stefvhuynh]

continued in #956