Initial version

The goal for the initial version is to have a basic working switch.
At this stage it is not my goal to implement any of the protocol extensions yet.

This version should support the following features:

- crypto
- line management
- channel management
- DHT, peer management
- application level channel API
- compatibility with the Node implementation

To do list:

- [x] improve packet acking
- [x] broken line detection
- [x] broken channel detection
- [x] clean shutdown
- [x] improve line opening