1.6.0 version

• Version 1.6.0 August 2020
  • Pull request by centic9 Model 1 constructor duplicate code removed.
  • Closed Issue 1 and 2 on github by adding support for high frequency MCU, such as ESP32
    The constructor of all models has a new parameter if set to true the code uses a custom "shiftin" function
  • Closed Issue 8 on github, LKM1638 bi-colour LED module support added (named Model 3 for purposes of library )
  • New function setLEDs added to turn on all LEDs at once, for model 1 and 3