fix opting out of scheduler

[mcfiredrill]

enabled: this.includeScheduler || true doesn't seem right to me, won't this always return true even if includeScheduler is undefined, null or false?

> a = undefined
undefined
> b = true
true
> a || b
true
> a = false
false
> a || b
true
> a = null
null
> a || b
true

It seems safer to explicitly set it to true.

[jamesdixon]

@mcfiredrill thanks for the breakdown of the true/false logic...lol

I missed it during the review of the PR that added this functionality, but yes, I'd agree that it would be better to explicitly set it.

Thanks for fixing this.

Cheers