consider "proportional leniency" and "lonely tasks"

[Malkiz]

I've read the documentation (cited by the README).
The docs say that the recommended behavior is "Definition 4: Combining proportional leniency and lonely tasks".

However I see nowhere in the code something that detects a "lonely task" in order to ignore it, and nothing that changes the "required quiet window size" (it's always 5000ms).

tti-polyfill/src/firstConsistentlyInteractiveDetector.js

Lines 282 to 292 in 4b5058e

	_longTaskFinishedCallback(performanceEntry) {
	log(`Long task finished`, performanceEntry);
	const taskEndTime = performanceEntry.startTime +
	performanceEntry.duration;
	this._longTasks.push({
	start: performanceEntry.startTime,
	end: taskEndTime,
	});
	this.rescheduleTimer(taskEndTime + 5000);
	}

Is there a plan to implement that behavior?
If not, I think it should be made clear in the README, because right now the code in this repo doesn't do exactly what the docs say it does.

[Malkiz]

To whom it may concern: I implemented the missing spec in this PR: #21

Also -
I included some fixes that haven't been merged yet from other PR's, better cleanup (to allow GC) and more configuration control.

I don't have the time or energy to comply with all the "contribution guidelines" or split this into multiple PR's.
Use it however you want, or don't, I don't mind either way.

Thanks.