Removing the legacy daemon

[cdecker]

Since we have almost reached feature parity it's time to remove the legacy daemon from the source tree. I think the following features are missing before we can do that:

• Support re-establishing connections on disconnect
• Support re-establishing connections after restarts
• Track funds across restarts
• Closing negotiation
• On-chain unilateral close
• On-chain penalty transaction

This being a rather large change, I would also propose a reorganization of the source tree:

• Remove source files that are not in use by the new daemon
• Remove protobuf-c as a dependency
• Rename the lightningd directory to src, and move all other source directories into that directory. This results in a clean top level directory with README.md with associated documentation, and the contrib directory.

Did I miss something @rustyrussell?

[rustyrussell]

Ok, added some points. I'm working on connection re-establishment, which means cleaning up the state transitions so we can tell exactly where we are when a reconnect comes in.

Then I'll need the database parts to restart the daemon, and do similar logic.

The closing and on-chain handling are almost orthogonal, and can be done in parallel.