v1.2.2 to fix `DutyCycle` and `New Period` display bugs

Releases v1.2.2

1. Fix DutyCycle bug. Check float precisison of DutyCycle only sometimes working #3
2. Fix New Period display bug. Check random dropouts #4
3. Update examples

v1.2.1 to use `float` for `DutyCycle` and `Freq`, `uint32_t` for `period`. and to optimize code by not calculation in ISR

Releases v1.2.1

1. Use float for DutyCycle and Freq, uint32_t for period.
2. Optimize code by not calculation in ISR

v1.2.0 to fix `multiple-definitions` linker error, to improve accuracy, DutyCycle to be optionally updated at the end current PWM period instead of immediately, etc.

Releases v1.2.0

1. Fix multiple-definitions linker error. Drop src_cpp and src_h directories
2. DutyCycle to be optionally updated at the end current PWM period instead of immediately. Check DutyCycle to be updated at the end current PWM period #2
3. Add examples multiFileProject to demo for multiple-file project
4. Improve accuracy by using double, instead of uint32_t for dutycycle, period. Check Change Duty Cycle #1
5. Optimize library code by using reference-passing instead of value-passing
6. Update examples accordingly

v1.1.0 to add functions to modify PWM settings on-the-fly

Releases v1.1.0

1. Add functions to modify PWM settings on-the-fly
2. Add example to demo how to modify PWM settings on-the-fly

v1.0.0 to support ISR-based multi-channel PWM for SAM_DUE boards, using Arduino SAM core

Initial Releases v1.0.0

1. Initial coding to support SAM_DUE, etc. using Arduino SAM core

2. The hybrid ISR-based PWM channels can generate from very low (much less than 1Hz) to highest PWM frequencies up to 1000Hz with acceptable accuracy.