Promise support

New Feature

• All APIs now support async/await and promises

API - New

• gpio.waveTxStop(cb) Aborts the transmission of the current waveform.
  This function is intended to stop a waveform started in repeat mode. waveTxStop

API - Enhancement

• gpio.waveChainTx([{loop:x}, {waves: [wids]}, {delay:y}, {repeat:z}], cb)
gpioWaveChain
  Transmit a chain of waves represented by array of wave IDs [wids]. The chain can have loops, be separated by delays and repeated by inclusion of option objects.
  • loop : x, begins a loop. x can be anything
  • delay: y, insert of delay of y=0 to 65535 microseconds
  • repeat: z, repeat loop z=0 to 65535 times or forever if z=true