Please add a command to disable serial input

[ArizonaClark]

I would like to request a new command to ignore serial input (separate from the "ignore-RX on reset"), which would have the controller ignore anything happening on the serial RX line. (It should be "volatile" in that it goes away whenever the display is reset or power cycled, IMHO.) To maintain symmetry (always a good idea) there should also be disable commands for SPI and I2C. (At the risk of pointing out the obvious, if these were "non-volatile" [as is the "ignore-RX on reset"], it would be too easy to "brick" the processor, thus best to make them "volatile".)

For "why", please see this Forum thread: https://forum.sparkfun.com/viewtopic.php?f=63&t=53788