Frequency of PCA9685 can't be set on a per channel basis

[caternuson]

Re this thread:
https://forums.adafruit.com/viewtopic.php?t=197676

PR #67 undid the fix done with PR #13 and reintroduced issue #12.

[tekktrik]

Whoops, I'll take this. I'll see if there's a way to get both.

[tekktrik]

They should be able to get the new version on PyPI now!