- adds more defensive checks to make sure no unnecessary toggling happens on disabled buttons; this also fixes an up-to-now undiscovered bug where a toggle button with `.disabled` class would still have its `aria-pressed` toggled
- adds a set of explicit tests for the above case of disabled buttons and `aria-pressed`
- remove a now irrelevant (or at least very nonsensical) test for `<label>` containing both an actionable and a `hidden` `<input>`
- expand the test for disabled checkbox to also explicitly test starting conditions (used mainly in my debugging)
- ensure that `$btn[0].click()` is used to click checkboxes in tests, rather than the `click()` on the jquery object which is simply a shorthand for `trigger('click')` and does not actually trigger the browser default behavior
- remove the `preventDefault()` from the button handling, which was preventing correct keyboard functionality for checkboxes/radio buttons
- add extra logic to the button.js code to handle checkboxes correctly and avoid double-triggering as a result of mouse interactions (which saw the checkboxes being toggled twice, thus returning them to their original state)
- add logic that prevents the `checked` property from being added incorrectly for any inputs other than radio buttons and checkboxes
- added more tests (including the most basic test for a properly triggered fake checkbox button)
- work around Firefox bug #1540995 (which this code was hitting after removing the `preventDefault()`, due to Firefox's incorrect toggling of disabled checkboxes when programmatically (but not manually) activated with a `click()` event
- 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
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.
