drivers - cc110x_ng: Propose new CC110x driver implementation

This PR proposes a new implementation of the cc110x_ng driver and shows example usage for the MSB-IoT board. The new implementation features:
* Usage of the low-level periph driver functionality (making board-specific spi communication implementations obsolete)
* Implementation of the new netdev base interface (still WIP in some parts)

I know this implementation still leaves room for optimization because of a lot of duplicate code between the old and new driver. Proposals to slim the code are very welcome!

This PR depends on ~~#1770~~
That confuses me.

`NETDEV_PROTO_RADIO`'s description states `"Sends frames as defined by radio_packet_t"`, but the cc110x uses his own packet format `cc110x_packet_t`which differs. If the transceiver module is used, it is true that a received cc110x_packet is copied to a radio_packet and then handed to possible "upper layers". But I don't see that this justifies calling the device's protocol `NETDEV_PROTO_RADIO`.