Update normalize.css to v3.0.1
Run `grunt`.
Gruntfile.js: Remove default `report` option.
Add TOC entry for "Third-party libraries" callout section to JS docs
Change GA events to Universal Analytics
Revert upgrade to Universal Analytics

The Google Analytics account we use cannot currently be upgraded to Universal Analytics. In order to keep using Analytics, we have to stick with Classic for now.
Merge pull request #13194 from twbs/normalize.css-3.0.1

Update normalize.css to v3.0.1
Fix tooltip viewport example

- Move example to correct location docs/examples/
- Move custom JS and CSS into stand-alone files
- Update headers and footers
- Copy-editing
Fix HTML errors