Does class led can add pulse function use GPIO.pwm?

[Asynchronous Interruption #0]

led breath effect is also very practical,
so maybe can consider to add pulse function to the led class in led.py?
the effect will like mention in this article:

http://shumeipai.nxez.com/2015/11/18/saks-diy-tutorials-breathing-light.html

[Asynchronous Interruption #0]

I had implemented this function and sent a pull requests, thanks for the article.

[spoonysonny]

Thanks for your pull request, I will test it and try to merge in next days.