Fixed custom event bug and added more details to event

Added fallback for Custom Event support in older browsers

Added fallback for hidden attribute

Totally rewritten for better a11y

Better selector support

- Added optimize-js

- Removed unit tests

Fixed jump on .focus()

Don't run click handler on right-click or command/control + click

BREAKING CHANGES: accessibility improvements.

- Content is now available to screen readers when hidden.
- Active tab is brougth into focus.
- If keyboard user tabs to a focusable element in a hidden tab, the tab becomes visible.
- Made `toggle` an optional variable for `tabby.toggleTab` method.
- Exposed variables to the `callback` method for more developer flexibility.

Added escapeCharacters for safer querySelector handling