added Publisher Acks class and methods

This introduces one new class and two new methods within said class.

> puback
>   class-id: 85
>
>   puback.select{many : bit}
>     put the channel into one of the two publisher ack modes, namely
>     "ack publisher messages as soon as they arrive" or "let them
>     pile up a bit and ack many messages at once"; this cannot be
>     called on a transacted channel
>
>   puback.deselect{}
>     handle any outstanding acks, put the channel back in the normal
>     mode, then return

deps/rabbitmq_codegen/demo_extension.json

@@ -15,4 +15,4 @@
 	 "id": 555,
 	 "methods": [{"name": "one", "id": 1, "arguments": []}]}
     ]
-}
+}

deps/rabbitmq_codegen/puback-extension.json

@@ -0,0 +1,27 @@
+{
+    "extension": {
+        "name": "puback",
+	"version": "0.1",
+	"copyright": "Copyright (C) 2010 SpringSource"
+    },
+    "domains": [
+    ],
+    "constants": [
+    ],
+    "classes": [
+    	{"name": "puback",
+	 "id": 85,
+	 "methods": [
+	     {"name": "select",
+              "id": 10,
+              "arguments": [
+	      	  {"type": "bit", "name": "many", "default-value": false}
+	      ]},
+             {"name": "deselect",
+              "id": 20,
+              "arguments": [],
+              "synchronous": true
+             }
+	 ]}
+    ]
+}