v1.2.0 to optimize speed with new `setPWM_DCPercentageInt_manual` function to improve speed almost 500 times compared to `setPWM`, to add many examples, and a breaking change to modify `setPWM_manual` function to take `16-bit` dutycycle instead from merely `0-100` for better accuracy

Releases v1.2.0

1. Optimize speed with new setPWM_DCPercentageInt_manual function to improve speed almost 500 times compared to setPWM
2. Add example PWM_manual to demo how to correctly use PWM to generate waveform. Check About DCValue in setPWM_manual #2
3. Add example PWM_SpeedTest to demo the better speed of new setPWM_DCPercentageInt_manual function
4. Breaking change: Modify setPWM_manual function to take 16-bit dutycycle instead from merely 0-100 for better accuracy
5. Modify example PWM_Waveform to adapt to breaking change of setPWM_manual function
6. Improve README.md so that links can be used in other sites, such as PIO
7. Bump up to v1.2.0 to sync with other Fast PWM libraries