v1.0.0 for AVR Slow PWM

### Initial Releases v1.0.0

1. Initial coding to support **AVR boards, such as Mega-2560, UNO,Nano, Leonardo, etc.**, etc. using AVR core

2. The hybrid ISR-based PWM channels can generate from very low (much less than 1Hz) to highest PWM frequencies up to 500Hz with acceptable accuracy.

Author: khoih-prog