Update scrollspy.js

Scrollspy target in tab content does not work properly. Calling .parents('.active') will return all parents with an active class (including the tab pane). Changing this line to .parentsUntil(this.options.target, '.active') should resolve the issue. This will scope the query to only search for active elements inside the scrollspy target.
Added unit test for removing only active class from within the scroll spy key.
Fix: IE10 or lower incorrectly determines the scrollheight of the body. Use document.documentElement for IE. To make this browser agnostic, the maximum scrollheight of both body and documentElement is used.
Fix: IE10 or lower incorrectly determines the scrollheight of the body. Use document.documentElement for IE. To make this browser agnostic, the maximum scrollheight of both body and documentElement is used.
Add Embed responsive utility
Merge branch 'responsive-embed' of https://github.com/boulox/bootstrap into boulox-responsive-embed

Conflicts:
	dist/css/bootstrap.css.map
	dist/css/bootstrap.min.css
refactored and renamed grid mixins
Added .list-group-item.disabled

Added support for disabled List group item.
Update variables.less
grunt with new mixins
grunt
Make both .scale(X) and .scale(X, Y) both work
add .sr-only-focusable; fixes #12259
update docs to include+use .sr-only-focusable
Documents #10140
Merge branch 'master' into document_popover_focus
Add initial right and left properties to offcanvas example for transitions.
Merge branch 'master' into pr/12412

Conflicts:
	dist/css/bootstrap-theme.css.map
	dist/css/bootstrap.css.map
	dist/css/bootstrap.min.css
	docs/assets/js/customize.min.js
	docs/assets/js/raw-files.min.js
	docs/dist/css/bootstrap-theme.css.map
	docs/dist/css/bootstrap.css.map
	docs/dist/css/bootstrap.min.css
	test-infra/npm-shrinkwrap.canonical.json
Merge pull request #12695 from martikaljuve/offcanvas-transition

Fixed transitions on offcanvas example by adding initial left and right properties
rm BrowserStack testing from build