Philipstv

- **fix**: Do not leave `PhilipsTVAPI` instance with invalid credentials on failed pairing.

- **breaking**: `set_auth` method on `PhilipsTV` and `PhilipsTVAPI` is replaced by `auth` property.
- **feat**: `auth` property is exposed on `PhilipsTVRemote` as well.
- **feat**: `PhilipsTVAPI` and `PhilipsTVRemote` expose read-only `host` property.
- **feat**: `PhlipsTVAPI` now raises exceptions: `PhilipsTVAPIUnauthorizedError`, `PhilipsTVAPIMalformedResponseError`.
- **refactor**: Better error message for exceptions.

- **docs**: Provided real documentation.
- **refactor**: Removed `PhilipsTVInterface`. `PhilipsTVAPI` now expects just a `PhilipstTV` instance.
- **refactor**: Removed `APIModel` base class, `APIObject` is used now.
- **refactor**: Made `philipstv.model.base` module public.

First release!