Shows a popup dialog message via System Events daemon.

        `title`
            Notification title.
        `message`
            Notification message.

def _osx_popup(title, message):
    """ Shows a popup dialog message via System Events daemon.

        `title`
            Notification title.
        `message`
            Notification message.
        """

    message = message.replace('"', '\\"')  # escape message

    # build applescript
    script = """
     tell application "System Events"
       display dialog "{0}"
     end tell""".format(message)

    # run it
    common.shell_process(['osascript', '-e', script])