Max sweep delay

[alexcjohnson]

@AdriaanRol re #44 - this PR adds a max_sweep_delay to argument to StandardParameter, along with the existing sweep_delay argument. If you give both, then we try to wait sweep_delay but don't generate a log warning unless the delay is longer than max_sweep_delay.

I also changed it so negative delays don't compound - that is, if you have one instance of too long a delay, the loop won't attempt to make up the difference in the next iteration, and will not keep adding to the time error.

And for calculating delay times I switched from datetime.now() to time.perf_counter() - which is relative, not absolute, time, but it is much higher resolution.

[AdriaanRol]

Looks good but I am a bit confsed with the log catcher in the utils.helpers. I thought in the end we decided not to catch logging messages or is this only there for testing purposes?

[alexcjohnson]

Looks good but I am a bit confsed with the log catcher in the utils.helpers. I thought in the end we decided not to catch logging messages or is this only there for testing purposes?

Right, only for testing purposes. I just put it in there because I needed it across multiple test files, and I could imagine people finding use cases for this down the line - like if you want to do something nice with log messages in the GUI.

[AdriaanRol]

Sounds good 💃