Merge remote-tracking branch 'upstream/3.0.0-wip' into 3.0.0-wip

* upstream/3.0.0-wip: (42 commits)
  Rename class name in placeholder
  Fixes #8154: enforce full width `.navbar-nav.pull-right` in mobile
  Fixes #8159: Be more specific about disabled inputs to avoid iOS bug
  Fixes #8093: Removes invalid focus styles on inputs
  run make on previous commit
  Fixes #7730: Better hiding of empty titles in popovers
  Run make on last commit
  Use `@font-family-base` for headings font-family variable
  run make on @nextgenthemes last commit
  rename '.navbar .nav' to '.navbar-nav'
  Add heading font family variable
  Offcanvas example update
  Fixes #8001: add IDs for example inputs
  Add missing property to form-horizontal docs
  Add support for `tr`, `th`, and `td` to responsive utilities
  run make on last commit
  docs/javascript.html: backticks -> <code>
  Use correct font-size to calculate input-heights
  Addresses #8199: darker default button
  Add note about Jekyll version per #8195
  ...

Conflicts:
	README.md
	docs/assets/js/bootstrap.min.js
	package.json
Grunt-task no longer copies over all JS files to docs
Add note about grunt-cli installation in Readme
Fix task `grunt run`