Add interfaces for Api and Token
Update README
Use Request data as []byte instead of url.Values
Add RegisterAddon method

This also allows to send data in json format,
not only as url encoded content.
Version 0.3.0

* Introduce custom cloudControl structure types
* Add possibility to create custom API instances
* Add custom Token source URL
* Add custom Add-on register URL and RegisterAddon methods
* Create Api and Token interfaces, so Requests uses them
* Request data is now also accepted as JSON
* Improve documentation
* Fix of bugs