Add blink-pattern functionality to Atm_led

[dsjstc]

Allows an LED object to blink in a pattern specified in a byte array. Each element in the array is a multiplier for the on time. I wanted this so I can chain up blinked error codes.

Also, resetting the counter when state() == OFF seems useful for any kind of repeat, not just patterns.

[jbarchuk]

Bump. I like this.

[00benallen]

@tinkerspy bump

[tinkerspy]

I would prefer this functionality to be in a separate library and not in the standard Atm_led machine perhaps under the name Atm_led_pattern. We could put it under contributed in the Wiki.

https://github.com/tinkerspy/Automaton/wiki/Contributed