protofsm: add ability for state machine to consume wire msgs

In this commit, we add the ability for the state machine to consume wire
messages. This'll allow the creation of a new generic message router
that takes the place of the current peer `readHandler` in an upcoming
commit.

protofsm/daemon_events.go

@@ -8,7 +8,7 @@ import (
 	"github.com/lightningnetwork/lnd/lnwire"
 )
 
-// DaemonEvent is a special event that can be emmitted by a state transition
+// DaemonEvent is a special event that can be emitted by a state transition
 // function. A state machine can use this to perform side effects, such as
 // sending a message to a peer, or broadcasting a transaction.
 type DaemonEvent interface {