Add eventmachine support

This code was pinched from mvidner#52.
The original repo for that PR seems to have been deleted.

lib/dbus/bus.rb

@@ -235,6 +235,13 @@ def glibize
       end
     end
 
+    def eventmachinize
+      require File.join(File.dirname(File.expand_path(__FILE__)), "loop-em")
+
+      conn = ::EventMachine.watch(@message_queue.socket, Loop::EventMachine::Reader, self)
+      conn.notify_readable = true
+    end
+
     # FIXME: describe the following names, flags and constants.
     # See DBus spec for definition
     NAME_FLAG_ALLOW_REPLACEMENT = 0x1

lib/dbus/loop-em.rb

@@ -0,0 +1,19 @@
+require 'eventmachine'
+
+module DBus
+  module Loop
+    module EventMachine
+      class Reader < ::EventMachine::Connection
+        def initialize(parent)
+          @parent = parent
+        end
+
+        def notify_readable
+          @parent.dispatch_message_queue
+        rescue EOFError
+          detach
+        end
+      end
+    end
+  end
+end