Reorder post hooks and execute_result message

Following IPython, messages and hooks in execute_request is ordered the
following way:

1. Send execute_input message if the request is not silent
2. Call pre_execute hooks
3. Call pre_run_cell hooks if the request is not silent
4. Run cell code
5. If the result is not null and the request is not silent,
   perform display the result and send execute_result message
6. Call post_execute hooks
7. Call post_run_cell hooks if the request is not silent
8. Send execute_reply message

Author: mrkn

lib/iruby/kernel.rb

@@ -134,14 +134,17 @@ def execute_request(msg)
         content[:execution_count] = @execution_count
       end
 
+      unless result.nil? || silent
+        @session.send(:publish, :execute_result,
+                      data: Display.display(result),
+                      metadata: {},
+                      execution_count: @execution_count)
+      end
+
       events.trigger(:post_execute)
       events.trigger(:post_run_cell, result) unless silent
 
       @session.send(:reply, :execute_reply, content)
-      @session.send(:publish, :execute_result,
-                    data: Display.display(result),
-                    metadata: {},
-                    execution_count: @execution_count) unless result.nil? || msg[:content]['silent']
     end
 
     def error_content(e)

test/iruby/kernel_test.rb

@@ -70,7 +70,7 @@ def inspect
       @kernel.execute_request(msg)
 
       assert_equal({
-                     msg_types: [ "execute_input", "execute_reply", "execute_result" ],
+                     msg_types: [ "execute_input", "execute_result", "execute_reply" ],
                      execute_reply: {
                        status: "ok",
                        user_expressions: {},