Store Helper to bind namespaced actions and organize methods

[drobtravels]

I wrote a Store mixin for my application and was curious if other people had similar issues and were interested in a PR.

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I have a Store in my application with a very large number actions to bind to, so my initialize method originally looking something like this.

this.bindActions(
 constants.widgets.new.pending, this.onWidgetNewPending,
 constants.widgets.new.success, this.onWidgetNewSuccess,
 constants.widgets.new.error, this.onWidgetNewError,
 constants.widgets.update.pending, this.onWidgetUpdatePending
 // The pattern continues for a while... );

This worked fine, but bothered me for a few reasons

1. The code is more verbose the needed, considering it all follows a similar pattern, and the actions are already described in the constants
2. By the time I repeated this a few times, the store was hundreds of line of code with no organization enforced.

To address this, I wrote a utility function autoBindActions which takes in an object of high level namspaces as keys, and an array of lower level namespaces as the value.

It roughly does something like this:

1. Binds the store to all actions defined in the Flux constants under the provided namespaces
2. When the Store receives one of these actions from autoBindActions, it checks if the Store has a handler defined for the higher level namespace (ie widgets), and checks for an appropriate function in that handler if so, using a pattern like onNewPending(). This allows me to logically organize the functions of my Store into separate objects. If a handler doesn't exist, it checks for the appropriate function in the Store, and if that function exists calls a generic function to handle this action (ie onPending())

The store now looks like this

 this.autoBindActions({
  widgets: ['new', 'update', 'delete'],
  categories: ['load', 'subCats', 'scripts']});

// further down in the store, I setup the handlers
categoriesHandler: App.Flux.StoreHandlers.Category,
widgetsHandler: App.Flux.StoreHandlers.Widget

Right now this code is a mixin slightly customized for my needs and in CoffeScript, so I wanted to gauge interest before I rewrote it in legible JS, etc. Obviously the details can be changed / debated once I put in the PR.