Allow NULL as value for id's #18
Description
When using the create action, we can decide whether to create a new record, or to update an existing one. CiviCRM API v3 allows us to do that easiliy: "if you pass an 'id' as a parameter, one record will be modified". Instead, one record will be created.
In versions v1.0-beta and v1.1, we could decide if we wanted to create a new record or update an existing one by passing -or not- id as a one of the parameters.
From v1.2, we'll be able to do an additional thing. If an id parameter is specified, it will be included in the API call only when its corresponding value is not NULL.
The new behavior will allow us to create steps where a record will be created or updated depending on the value of one of the columns (probably called id) of the rowset.