Added sqs.close_connection for issue appoxy#16.

lib/sqs/sqs.rb

@@ -70,6 +70,11 @@ def initialize(aws_access_key_id=nil, aws_secret_access_key=nil, params={})
       @interface = SqsInterface.new(aws_access_key_id, aws_secret_access_key, params)
     end
 
+    def close_connection
+      @interface.close_connection
+    end
+
+
     # Retrieves a list of queues.
     # Returns an +array+ of +Queue+ instances.
     #