merge 4.1.x into 4.x

[dhalbert]

Let's use 4.x for bugfixes to version 4. There are fixes in 4.x that were not in 4.1.x and vice versa. I'll make another PR for the other way. We weren't consistent about which one we used. Or maybe get rid of the 4.{0,1}.x branches, since it's confusing?

[jepler]

The changes all look like sensible stuff. I can't speak to the question of how to manage the v4-ish branches but I could sure show up at a special in the weeds section to talk about it if that's helpful

[tannewt]

I generally prefer 4.1.x and 4.x to be separate if 4.x work will end up as 4.2.0. In general, I'd prefer more specific branches like 4.1.x over more general ones.

[dhalbert]

I generally prefer 4.1.x and 4.x to be separate if 4.x work will end up as 4.2.0. In general, I'd prefer more specific branches like 4.1.x over more general ones.

Sounds fine -- I have submitted a reverse PR to make the two branches identical. Do you feel that the CPX stack-size updates and the new frozen libs are 4.1.1 or 4.2.0? It is an API enhancement from the point of view of the CPX library, but nothing else. And boards other than CPX are not affected at all, so maybe 4.1.1?

[tannewt]

Either one works for me.