Allow document objects to be passed as operation inputs

Right now, if a document is passed as an input of an operation, it's id is set as the input instead of the document object, which is a problem if the input is a document model for a document that isn't created yet.

This can be done by replacing this line:

this._automationParams.input = input.uid;

by:

this._automationParams.input = input.uid || input;