Added a provider to allow the ES client to be accessed via the resource request scope

[jamhall]

Hello,

You can now access the client via the the request scope:

By registering the provider in the application run method:

environment.jersey().register(EsProvider.binder(managedClient));

You will be able to access the client via an injected parameter in the resource method:

public List<Message> getMessages(@Context Client es) {
    SearchResponse response = es.prepareSearch etc.
}

Please let me know If I haven't correctly implemented the provider...

Thank you for the project!

[coveralls]

Coverage decreased (-7.2%) to 72.18% when pulling 0a5f469 on jamhall:master into 5a8e637 on dropwizard:master.

[coveralls]

Coverage decreased (-7.2%) to 72.18% when pulling 0a5f469 on jamhall:master into 5a8e637 on dropwizard:master.

[coveralls]

Coverage decreased (-6.6%) to 72.727% when pulling 6112eb5 on jamhall:master into 5a8e637 on dropwizard:master.