Allow options object to be passed into Collection.create()
Merge pull request #416 from adambiggs/collection-create-options

Allow options to be passed into Collection.create()
Merge branch 'master' of github.com:spine/spine
only set the content type header on POST and PUT, otherwise leave empty or allow user to override. Deals with some servers treating an empty body as invalid json when parsing requests.
fix tests
Merge branch 'master' of github.com:spine/spine
Merge branch 'master' into listenEvents
rebuild after merge from master