Added ability to IO.select websockets

examples/websockets.ru

@@ -13,6 +13,7 @@ class Test < Landline::App
       puts "Client closed read connection"
     end
     socket.write("Hi!")
+    puts IO.select([socket]).inspect
     while (response = socket.read)
       if response
         puts "Client wrote: #{response.inspect}"

lib/landline/extensions/websocket.rb

@@ -171,6 +171,12 @@ module Landline
         close_write if @writable
       end
 
+      # Obtain internal IO object
+      # @return [IO]
+      def to_io
+        io
+      end
+
       attr_reader :io, :readable, :writable
 
       private