* change api and ApiClient to return cancellable NSURLSessionTasks instead of NSNumber
* define a configuration protocol for custom configurations, which can be passed to api clients instead of a global configuration, provide a default implementation with a singleton option
* integrate a workaround for a current JSONModel concurrency bug
* update to new ISO8601 pod
* add missing call to super
* integrate new templates into codegen
* updates documentation templates
* updates petstore objc generated code
* fixes objc client tests