'Adds a command to the checksummed main command queue if printing, or
sends the command immediately if not printing'

def send(self, command, wait=0):

    if self.online:
        if self.printing:
            self.mainqueue.append(command)
        else:
            self.priqueue.put_nowait(command)
    else:
        self.logError(_('Not    connected    to    printer.'))
