Pycloudflare

* Switch to Demands >= 4.0.0

* Include `README.rst` file in package, since `setup.py` depends on it

* Assign `_data` to the returned result as the `Record` meta values change on
`save`.

* Move attributes required for SRV records into the correct field.

* Add SRV record support to allow for the creation of SRV DNS records.
* Rename `service` attributes of models to `_service`.
* Use `record_type` instead of `type` in `create_record` signature.
* Make `content` parameter to `create_record` optional.
* Use `kwargs` for `priority` parameter in `create_record`.

* Raise `ZoneNotFound` instead of `IndexError` when zone isn't found.