Make Stream usable in a supervision tree

Supervisors don't tolerate a secondary startup step.

README.md

@@ -21,10 +21,6 @@ In order to setup a connection to listen for AMI events, one can do:
 ```ruby
 require 'ruby_ami'
 
-stream = RubyAMI::Stream.new '127.0.0.1', 5038, 'manager', 'password',
-                              ->(e) { handle_event e },
-                              Logger.new(STDOUT), 10
-
 def handle_event(event)
   case event.name
   when 'FullyBooted'
@@ -34,28 +30,32 @@ def handle_event(event)
   end
 end
 
-stream.run # This will block until the actor is terminated elsewhere. stream.async.run is also available if you need to do other things in the main thread.
+stream = RubyAMI::Stream.new '127.0.0.1', 5038, 'manager', 'password',
+                              ->(e) { handle_event e },
+                              Logger.new(STDOUT), 10
+
+Celluloid.join(stream) # This will block until the actor is terminated elsewhere. Otherwise, the actor will run in its own thread allowing other work to be done here.
 ```
 
 It is also possible to execute actions in response to events:
 
 ```ruby
 require 'ruby_ami'
 
-$stream = RubyAMI::Stream.new '127.0.0.1', 5038, 'manager', 'password',
-                              ->(e) { handle_event e },
-                              Logger.new(STDOUT), 10
-
-def handle_event(event)
+def handle_event(event, stream)
   case event.name
   when 'FullyBooted'
     puts "The connection was successful. Originating a call."
-    response = $stream.send_action 'Originate', 'Channel' => 'SIP/foo'
+    response = stream.send_action 'Originate', 'Channel' => 'SIP/foo'
     puts "The call origination resulted in #{response.inspect}"
   end
 end
 
-$stream.run
+stream = RubyAMI::Stream.new '127.0.0.1', 5038, 'manager', 'password',
+                              ->(e) { handle_event e },
+                              Logger.new(STDOUT), 10
+
+Celluloid.join(stream) # This will block until the actor is terminated elsewhere. Otherwise, the actor will run in its own thread allowing other work to be done here.
 ```
 
 Executing actions does not strictly have to be done within the event handler, but it is not valid to send AMI events before receiving a `FullyBooted` event. If you attempt to execute an action prior to this, it may fail, and `RubyAMI::Stream` will not help you recover or queue the action until the connection is `FullyBooted`; you must manage this timing yourself. That said, assuming you take care of this, you may invoke `RubyAMI::Stream#send_action` from anywhere in your code and it will return the response of the action.

lib/ruby_ami/stream.rb

@@ -29,6 +29,7 @@ def initialize(host, port, username, password, event_callback, logger = Logger,
       @lexer = Lexer.new self
       @sent_actions   = {}
       @causal_actions = {}
+      async.run
     end
 
     [:started, :stopped, :ready].each do |state|

spec/ruby_ami/stream_spec.rb

@@ -34,7 +34,6 @@ def mocked_server(times = nil, fake_client = nil, &block)
       mock_target.should_receive(:receive_data).send(*(times ? [:exactly, times] : [:at_least, 1])).with &block
       s = ServerMock.new '127.0.0.1', server_port, mock_target
       @stream = Stream.new '127.0.0.1', server_port, username, password, lambda { |m| client.message_received m }
-      @stream.async.run
       fake_client.call if fake_client.respond_to? :call
       Celluloid::Actor.join s
       Timeout.timeout 5 do