Added initial state functionality to modules.

[lucasconstantino]

No description provided.

[sebas5384]

@lucasconstantino I think this PR is doing some refactors which could be in different PR in order to review it better.

The code of which enables the initial state for modules is really great, and I think we can do it in a way it isn't close the door to Immutable libraries (for example ImmutableJS).

Given that I think we can do PR which enables the developers to extend the processModules and implement more behaviors like this one.

@recidive and @lucasconstantino how we could do the initial state handled in way we don't loose compatibility with immutable libraries?

[sebas5384]

@lucasconstantino I did PR over this issue, to avoid the mutation of state object passed as reference.
Let me know what you think, @recidive gives me his "ok", so if you agree on this please make the merge of lucasconstantino/redux-boot@initial-state...sebas5384:patch-1 and I'll merge this PR right away!

[lucasconstantino]

Done ;)

[sebas5384]

@lucasconstantino awesome!!

Oh! I think we forgot the documentation, so I'll document it and send you a PR later 👍