Add support for camel-casing ActionController::Parameters

[jcarlson]

Steps to reproduce

class MyController < ApplicationController

  def foo
    props = params.permit(:foo_bar, :baz_etc)
    render component: 'foo', props: props, camelize_props: true
  end
end

Note that the given props are not properly camelized when rendered to the React component. This is because React.camelize_props does not recognize ActionController::Parameters as a valid hash and returns it as-is.

Expected behavior

React.camelize_props should camelize instances of ActionController::Parameters.

Actual behavior

React.camelize_props does not camelize instances of ActionController::Parameters.

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I was going to submit a PR, but I noticed that the gem spec only requires Rails 3.2, so I wasn't sure what the best approach might be for testing with a class that didn't appear until Rails 4.

[BookOfGreg]

@jcarlson I would still welcome a PR, if it works on some versions of Rails then it's more progress than most make.

On earlier versions we tend to follow the if defined?(NewThingy) pattern.

I agree, this would be a convenient feature.