pkg: hide it by moving to _pkg.dev

The idea here is to preserve the history of `dev` branch development and its
code when merging with the `master`. Later this code could be moved into the
masters code where appropriate.

_pkg.dev/wire/command/command.go

@@ -0,0 +1,29 @@
+package command
+
+// Size of command field in bytes
+const (
+	Size = 12
+)
+
+// Type represents the type of a message command.
+type Type string
+
+// Valid protocol commands used to send between nodes.
+const (
+	Version    Type = "version"
+	Mempool    Type = "mempool"
+	Ping       Type = "ping"
+	Pong       Type = "pong"
+	Verack     Type = "verack"
+	GetAddr    Type = "getaddr"
+	Addr       Type = "addr"
+	GetHeaders Type = "getheaders"
+	Headers    Type = "headers"
+	GetBlocks  Type = "getblocks"
+	Inv        Type = "inv"
+	GetData    Type = "getdata"
+	Block      Type = "block"
+	TX         Type = "tx"
+	Consensus  Type = "consensus"
+	Unknown    Type = "unknown"
+)