minor improvements to text placement in qtconsole

* allow `before_prompt=True` behavior to have effect during raw_input
* append 'cannot restart' message before the prompt, so it doesn't
  get mixed up with input.

IPython/frontend/qt/console/console_widget.py

@@ -772,7 +772,7 b' class ConsoleWidget(LoggingConfigurable, QtGui.QWidget):'
         """
         # Determine where to insert the content.
         cursor = self._control.textCursor()
-        if before_prompt and not self._executing:
+        if before_prompt and (self._reading or not self._executing):
             cursor.setPosition(self._append_before_prompt_pos)
         else:
             cursor.movePosition(QtGui.QTextCursor.End)

IPython/frontend/qt/console/frontend_widget.py

@@ -597,7 +597,9 b' class FrontendWidget(HistoryConsoleWidget, BaseFrontendMixin):'
                     self.kernel_manager.restart_kernel(now=now)
                 except RuntimeError:
                     self._append_plain_text('Kernel started externally. '
-                                            'Cannot restart.\n')
+                                            'Cannot restart.\n',
+                                            before_prompt=True
+                                            )
                 else:
                     self.reset()
             else:
@@ -605,7 +607,9 b' class FrontendWidget(HistoryConsoleWidget, BaseFrontendMixin):'
 
         else:
             self._append_plain_text('Kernel process is either remote or '
-                                    'unspecified. Cannot restart.\n')
+                                    'unspecified. Cannot restart.\n',
+                                    before_prompt=True
+                                    )
 
     #---------------------------------------------------------------------------
     # 'FrontendWidget' protected interface