doc that popover content() is given the element as an arg; fix #13175
Update normalize.css to v3.0.1
Run `grunt`.
Add TOC entry for "Third-party libraries" callout section to JS docs
Change GA events to Universal Analytics
Add equal-height grid columns as an experimental example.

Based on @pete-otaqui's work from #11851
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
Add Gist & Customizer URLs to customized files & config.json

Fixes #9951
Fixes #12865
grunt dist
Merge pull request #13205 from twbs/fix-9951

Add Gist & Customizer URLs to customized files & config.json
use glob instead of fs.readdirSync since /less now has subdirs
rename generateCustomCSS to generateCustomLess for accuracy
enhance customizer to handle transitive Less @import-s
grunt update-shrinkwrap build-customizer dist
Merge pull request #13047 from twbs/fix-customizer

Fix customizer (see #13043)
fixes #13216

change `@zindex-popover` and `@zindex-tooltip` values to be greater than
those set for `@zindex-modal` allowing tooltips and popovers to be
displayed in front of modals (and all other content).
Merge pull request #13190 from twbs/fix-13175

doc that popover content() is given the element as an arg