Add `incluce_variants` to unit options (see #3) 

Merge pull request #2 from oveleon/feature/broker Add brokers route

Update contact options (`broker_id` added) 

Update contact options 

Allow to pass custom fields for the endpoints `unit` and `contact` 

Adding the `internal_brokerage` field for UnitOptions 

Adding the `sold_price` field for UnitOptions 

Fix the `deal_pipeline_id` option field and add the `broker_id` for q… …uerying deals

Fix: The object category could not be set 

[Update] Add additional mail options and adjust payload for request