option to serialize attributes in camelCase

[barsh]

This PR resolves closes #188.

This PR includes an option to serialize/deserialize attributes as camelCase instead of kebab/dash notation.

public static void Register(HttpConfiguration config)
{
    // ...

    var jsonApiConfig = new JsonApiConfiguration
    {
        PropertyNameConverter = new CamelCasePropertyNameConverter()
    };
    config.ConfigureJsonApi(jsonApiConfig);

    // ...
}

[barsh]

@joukevandermaas I'll do some more work on this over the weekend. Have you considered creating a Gitter for this repo? It's a nice way for consumers and contributors to collaborate on open source projects. Here's a Gitter for a json api repo for rails.

[joukevandermaas]

@barsh I had not considered it, but I'm definitely open to it. Thanks for the suggestion, I'll take a look.

[barsh]

@joukevandermaas my original goal for this PR was to allow attributes be renamed like this:

Attribute(nameof(Person.FirstName), renameAs: "firstName")

I realized significant effort would be required to make that work, because sorting and filtering does not work if you rename an attribute to something other than the camelCase, PascalCase, or kebab-case equivalent of the original attribute name.

So I have reworked this PR for the purpose of providing an option to serialize attributes with camelCase. I revised my opening comment to match this change of mindset.

I'm submitting this for reivew, bc I think my work is done here.

[barsh]

@joukevandermaas this PR is ready for review, including documentation and unit tests.

[barsh]

@joukevandermaas my last commit should address the backwards compatibility issues. Let me know if you see anything else.