`shrink-to-fit=no` is not needed anymore - Apple removed the need for it from iOS9.3 onwards

See https://www.scottohara.me/blog/2018/12/11/shrink-to-fit.html and https://github.com/h5bp/html5-boilerplate/issues/2102

...as it always evaluates to true

Dynamically set/remove `aria-modal="true"` when a modal is shown/hidden

Also remove close button everywhere just let it when autohide is set to false

Having variables initialised from start `_isTransitioning` is better.
Would be better to add an eslint rule to check for undeclared variables use.
Reordered enter checks for `show` and `hide` by priority.

I'm using Tab.js with remove function and get an error "TypeError: container is undefined [more info]", with this check the error is fixed.

Firefox currently seems extremely fickle - with `pan-y` if fires pointercancel as soon as a touch strays even a pixel or so vertically.
While `touch-action: pan-y` would be ideal (allowing users to scroll the page even when their finger started the scroll on the carousel), this prevents a swipe that isn't perfectly/only horizontal to be recognised by Firefox.

in particular, no need to use originEvent, and preventDefault() only needed for touch events