Add 307 to codes

Fixes #49.

Conflicting definitions per https://www.alien.net.au/irc/irc2numerics.html:

- RPL_USERIP (?)
- RPL_WHOISREGNICK (Bahamut, Unreal)
- RPL_SUSERHOST (AustHex)

Accordingly, don't give it a name yet, just a type.

Author: Throne3d

lib/codes.js

@@ -179,6 +179,9 @@ module.exports = {
         name: 'rpl_nowaway',
         type: 'reply'
     },
+    307: {
+        type: 'reply'
+    },
     311: {
         name: 'rpl_whoisuser',
         type: 'reply'