Don't require accordion sections to be siblings.

This will allow accordions that have their sections separated into
different block-grid areas.
Improve documentation.
dropdown arrow animation fix for small screen
reveal position top when using 'fade' animation
fix indentation
Fix-for-issue-#4382
Fixed issue with top bar stuck open on screen widths below the large breakpoint
removed test.html file
offcanvas animation fix for anchor tags

A fix for #4411. I have added bind event for transition end, that triggers the href jump once the transition is done. I am not sure if it is the proper way. But it works and i have tested in latest versions of firefox and chrome.
Don't require accordion sections to be siblings.

This will allow accordions that have their sections separated into
different block-grid areas.
Improve documentation.
Merge remote-tracking branch 'github/accordion-split-sections'
Allow accordion event to trigger on embedded accordion sections.

Fixes issue #4420.
Does for the top-bar what #3828 fixed off-canvas
Add test for block-grid accordion.
Optimized selectors in another tight loop

Found another selector repeat inside of a tight loop. Cached the selector before entering loop
Removed duplication of rules in select styling and simplified background position handling for RTL.
Added an option to explicitly set the select focus background colour.
Stop propagation of click events on the background

This is to prevent the bubbled-up clicks from triggering changes behind the modal overlay (e.g., the auto-closing of open dropdowns).
Fixed $select-hover-bg-colour not used in Mozilla.
Changed code such that it is only the header of an active accordion item is styled -navigation-active-bg-color