Whitespace cleanup.

In addition to global headers (which were doable before), this allows for global
path param replacement in URLs.

This has cropped up in a few APIs over the internet and we're traditionally not provided
a good path to implementation. Before you would have to manually move the global param
around your application to every method call site onto a Retrofit interface. This new
interface provides a single place to manage these global params along with other
global headers (such as for authentication).

Given:

    @GET("/show/{apiKey}/{showId}/episodes")
    List<Episode> episodes(@Path("showId") String showId)

Usage:

    class FooInterceptor implements RequestInterceptor {
      @Inject @ApiKey String apiKey;

      @Override public void intercept(RequestFacade request) {
        request.addPathParam("apiKey", apiKey);
      }
    }

This also has the added benefit of saving an extra `List` allocation for global headers
since they are now set directly on the underlying `Request` via the facade interface.

Also move it to its own groupId.

Closes #137.

Move the HTTP client implementation behind interfaces which allow
for its substitution. A `Client` is a one-method class which takes a
`Request` object, executes an HTTP request represented by it
synchronously, and returns a `Response` object representing the HTTP
response entirely.

Since this is such a fundamental change all of the tests which interact
with and verify the client have been rewritten from scratch.

This commit also changes two behaviors which were previously present:

 * Implicit, form-encoded request bodies are no longer supported. Extra
   `@Named` params on a method is now invalid.
 * Multi-part requests are no longer implicit. Methods which submit
   multi-part request bodies must be annotated with `@Multipart`.

* Bump version to 1.0.0-SNAPSHOT.
* Conslidate 'http' and 'io' modules into a single 'retrofit' module.
* Remove native directory sync code and example.
* Renames 'examples' to 'samples'.

This is a short step on the road to HTTP body format agnostic support. And it's
not a pretty step, either.

* Reintroduce shake detection as its own module.
* Move YAFFS-specific directory sync to its own module.
* Focus HTTP and I/O modules.
* Queue module for `QueueFile` and future queue-related stuff.