This reverts commit 8bb35313.

This is no longer needed.

This reverts commit 9e5ec00d.

Unfortunately, we are getting too many timeouts.

It's slower, but since it runs only on Travis, we better be safe.

Also, enforce LF in clean-css.

see: https://github.com/twbs/bootstrap/issues/26847
in v4, destroy was replaced by dispose

The SSL certificate of the useiconic.com is expired

Fix paths to docs.

fixes #26476

* Add margin utils to the grid for fully functional grid control

* bump the max filesize

Fixes #26897

* Flexbox based sticky footer

* Update guide message

* Use utility classes instead of custom CSS

ref: https://github.com/twbs/bootstrap/pull/23881#issuecomment-337789596