Update README again

Signed-off-by: Rahix <rahix@rahix.de>

README.md

@@ -121,7 +121,7 @@ bc:set("some_noun", 4321)
 ### `BaseControl:get(noun, [timeout])`
 Get the value of a noun named `noun`.  `get` can not be called for verbs.
 If `timeout` is supplied, the call will return early if no response came before
-the timeout expired.
+the timeout expired.  `get` will return `nil` if a name is not known.
 ```lua
 local bc = require("bc"):finalize{"some_noun"}
 print("Value: ", bc:get("some_noun"))
@@ -166,7 +166,8 @@ If it is not known at this time, the listener is still installed in hope that
 the node will come online later.  `query` must be a valid query, chosen from
 `BaseControl.Query`.  A full list of currently supported queries was shown above.
 The `callback` function will get one argument:  The new value of the noun that
-triggered the event.
+triggered the event.  `listen` returns a unique id for the installed listener
+that could later be used to cancel it.
 
 ```lua
 bc = require("bc"):finalize{"some_noun"}
@@ -178,6 +179,21 @@ bc:listen("some_noun", bc.Query.Below(0), function(value)
 end)
 ```
 
+### `BaseControl:cancel(id)`
+Cancel a previously installed listener.  The id will be invalid after this call.
+```lua
+local listenid = bc:listen("some_noun", bc.Query.Change, function(value)
+  print("'some_noun' is now '"..value.."'")
+end)
+
+-- Later ...
+bc:cancel(listenid)
+```
+
+### `BaseControl:close()`
+End this base-controller and notify others of the local nouns and verbs going
+offline.  Close will also cancel all installed listeners.
+
 Introspection API
 -----------------
 The following methods give you insight into the network:
@@ -192,11 +208,13 @@ Whether `verb` is known at this time (either local or remote).  Note that even i
 a verb is known, calling it might still not succeed if the remote node exited
 without deregistering.  If you need to know for sure, call using `call_sync`.
 
-### `BaseControl:nouns()`
+### `BaseControl:nouns([local_only])`
-Returns a list of all known nouns (either local or remote).
+Returns a list of all known nouns (either local or remote).  If `local_only` is
+boolean true, only a list of local nouns will be returned.
 
-### `BaseControl:verbs()`
+### `BaseControl:verbs([local_only])`
-Returns a list of all known verbs (either local or remote).
+Returns a list of all known verbs (either local or remote).  If `local_only` is
+boolean true, only a list of local verbs will be returned.
 
 Network Configuration
 ---------------------