Thread request context through to GraphQL executor

[bendemaree]

This addresses the problem raised in #7; when graphql() is invoked, the current context value is not being passed to the executor (via context_value).

Here's a straightforward way to reproduce; if you run with and without the patch here, you'll see two different things printed:

importgrapheneclassQuery(graphene.ObjectType):
noop=graphene.String()
classSubscription(graphene.ObjectType):
ping=graphene.String(required=True)
asyncdefresolve_ping(root, info):
print(info.context)
yield"pong"asyncdefresolve_player_statistics(root, info):
passschema=graphene.Schema(query=Query, subscription=Subscription)

and (using WsLibSubscriptionServer):

asyncdefhandle_subscription(ws, path):
awaitsubscription_server.handle(ws, request_context={"foo": "bar"})

This will print None and {'foo': 'bar'} before and after this patch, respectively.

[SmileyChris]

Fixed