FlxGame#new()'s confusing zoom parameter

[JoeCreates]

Following my change in #1889 to make scrollbounds account for zoom, a couple of people have had issues due to the zoom parameter of FlxGame#new() not being set to 1 (#1976).

It seems that in both cases there was confusion about the meaning of said parameter, where it was interpreted to have an actual impact on the scale of the game, whereas it's actual meaning now seems to be "what value of zoom should count as not zoomed". My change did not take this into account and so does not work for other values in here. I believe it could be fixed simply by dividing the value of zoom that is used in updateScrollBounds by the game's defaultZoom, although this wouldn't help with the continued misinterpreting of the scroll parameter, which seems to have lost it's utility since the introduction of scale modes.

In the coming weeks when I have time I'll modify updateScrollBounds to account for other FlxGame zoom values. Is there any reason for this parameter to be kept long term, or should it ultimately be removed with the next batch of breaking changes?

[Gama11]

Looks like there's actually not a single demo that has Zoom != 1. So, yeah, I doubt it's really necessary anymore with scale modes...

[Gama11]

Does the fix in 96dccf0 look sensible?

[JoeCreates]

Yeah, that looks correct. :)

[buckle2000]

I changed Zoom to 3 and nothing happened. Is that a bug?
Flixel 4.2.0

[Mouradif]

Same here, the Zoom parameter in FlxGame's constructor doesn't seem to have any effect.
Also Flixel 4.2.0

[Geokureli]

Clearing out 5.0.0 tasks, was this completed?

[Geokureli]

I tried various demos with a zoom other than 1 and it didn't seem to have any effect on the "pixel size" like the documentation claims. I say we remove this property, and better teach scalemodes