Implement API support for options.match

When saving an entity with the API's "create" action, one can do an "insert or update" – e.g. if the ID is specified, then it will update the existing record. But this only works for the entity's primary-key – it doesn't work for business-keys (such as "name" or "email" or "contact_id+location_type_id" or "option_group_id+name"), so one needs to write boilerplate to lookup the ID. The "options.match" will provide a sugary way to update existing records without explicitly knowing the ID#.

(In support of CRM-13187)