Add a license header to bootstrap.scss

v4 - Rename .img-responsive class to .img-fluid

v4 - Fix Navbar at top of v4 Offcanvas example

Fix missing anchors and 404 errors.

Replace instances of 'control-label' with 'form-control-label'

[skip sauce]

clarifies that normalize.css is a dependency of reboot

Fix #17173

Fix #17166

Media vertical align flexbox classes

v4 - Force linebreaks after grid tier names in v4 grid docs

v4 - Fix link to narrow jumbotron example

v4 - Updated default navbar example to use responsive navbar

Combine size & square mixins into one

Update static form control example

Remove CSSLint references.

Document utility class .bg-inverse

v4: Conditional predefined grid classes

Semantic grid: add make-container-breakpoint

Fix several erroneous links in docs.

Fixed link to nav component from scrollspy documentation

Adds table-responsive class to docs table

(reported by ianhernandez in Slack)

Remove the unused Google fonts.

Apply !default to SCSS variables

Missed one variable :(

Accept elements as the tooltip / popover content