fix minor formatting issue
add models for account creation
fix toString for AccountDetail to call super
request params need a body for create
Split the json serialization out of the `ApiClient`.

We are going to need to serialize the json for the
`AccountCreateRequest` before we give it to the client.
This makes it clear the client should not hold the logic.
So I've made a functional `JsonSerializer` class with static
methods for going to and from json.
Implement the call to create an account.

+ Add the method to the `AccountsResource` interface
+ Add a few `create` helpers to the `BaseResource`
+ Make sure the `ApiClientImpl` uses the `RequestParams.getBody()`
+ Add a unit test
add the corresponding delete method for accounts
add an integration test for creating and deleting
Merge pull request #14 from orgsync/account-create

Account Creation