When piping to tio it will automatically enter "non-interactive" mode
which means it will not react to any input key sequences but simple read
the input stream and write it to the tty device.
This also means that ctrl-t q can not be used to quit and so tio would
hang forever when used in non-interactive mode.
This change allows to send the standard termination signal by pressing
ctrl-c on tio in non-interactive mode to make it quit.
