Fixes #7611: fix optgroup formatting for Firefox
Fixes #7474: Use `@input-height-base` in `.navbar-vertical-align()` for `.navbar-form`
Refactor readme to include directions on running jekyll locally
Update contributing file

* Remove notes on repo section
* Update hirearchy of coding standards sections
Back to getbootstrap.dev for jekyll
Fixed broken Customizer link for docs
Merge pull request #7945 from AJ-Acevedo/fix

Fixed broken Customizer link for docs
upgrade jshint to 2.1.2 for anton <3
remove jszip files