Add the `options` call to the Resource Query object

Version 2.9.1

PR: #82

Adds the ability to make an options request on the Resource query, which returns the response from the HTTP OPTIONS call.

Usage:

from gapipy import Client

client = Client(application_key='your_application_key')
opt = client.<resource>.options()

# opt is a `dict` that represents the OPTIONS response body
# resource is any resource query object available on the Client