* Refer to utility classes uses. Add Printing section

refer to (not navbar) classes used for newbies
navbars don't print, so add example of a print-only alternative

* typos, add links

typo in {% example %}
add links to component pages

* grammar

* Add a dropdown with divider to the main example

* change id name to stop travis error

I assume id="camelCase" is the standard for id names, rather than the clearly superior id="underscore_words"

* review changes

still like to emphasise the foreign utility classes in the main example
bg-light's name is self explanatory (so its obvious where to look it up), but mr-sm-2's name isn't at first

* review changes

* grammar

* .fixed-top/bottom don't reserve space on the screen

... as they are position:fixed. 
better wording welcome

* copyediting

- rewrite utils line and link to the utils pages
- restore the paragraphs to the plac...

* fixes migration forms guides

* removes container from Horizontal form

* adds col-form-label sizes on form docs

* removes .form-control-label from forms.scss

* add note to migration

* revert #23108, which had no bug but was a problem with the example code

* add example to the docs for future proofing

* move it up

Fixes #24311

Also, lock babel deps to 7.0.0-beta.2 so that we are on the safe side.

* Add dispose methods in our documentation

* Update buttons.md

The old ones are still being redirected.

1. Add `alt=""` for the Bootstrap logo
2. Replace the HTML entities with the unicode symbols
3. Refactor the badges to something that makes more sense to me
4. Change `Selenium Test Status` alt attribute to `Sauce Labs Test Status`
5. Use shields.io for the peerDependencies badge too
6. Add CSS and JS gzip size badges, shoutout to @ngryman
7. Add a few more trailing slashes to URLs
8. Change link to tooling setup to the website one

This is required for Sass v3.5+ compatibility.
See https://github.com/sass/sass/blob/stable/doc-src/SASS_CHANGELOG.md#backwards-incompatibilities----must-read and https://github.com/sass/sass/issues/2383

It was mistakenly the same as lightning.svg.

Using `rgba($white,1)` results in `white` instead of the hex.