* Prep for v4.3.0

* More updates for v4.3.0.

* rerun to build docs source map

- Move 4.1 docs to 4.2
- Update versions everywhere to 4.1.3 with release script
- Manually bump the shorthand version in package.json
- Add 4.2 to the versions docs page
- Update some redirects
- Fix tests asset URLs
- Bump Nuget and more

...as it always evaluates to true

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

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.

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

these may also be the cause of weird behavior in Chrome/Surface, where scrolling vertically triggers slide advance