- Renamed "Commands" to "builder"
- "Messages.parseMessage" to "Messages.parseBuffer"
- Changed to use private methods for "discardUntilNextMessage" and "buildFromBuffer"
- Cleaned up tests
I'v seen `RangeError: index out of range` crashes from nodes that don't
send it, when `bitcore-p2p` tries to `readUInt8()` the last bit.
This also adds `relay` property to `Peer` objects that is respected
when sending `Version` messages.