Merge branch 'master' into v4

Conflicts:
	Gruntfile.js
	_config.yml
	dist/css/bootstrap-theme.css
	dist/css/bootstrap-theme.min.css
	dist/css/bootstrap.css
	dist/css/bootstrap.css.map
	dist/css/bootstrap.min.css
	dist/fonts/glyphicons-halflings-regular.eot
	dist/fonts/glyphicons-halflings-regular.svg
	dist/fonts/glyphicons-halflings-regular.ttf
	dist/fonts/glyphicons-halflings-regular.woff
	docs/_data/glyphicons.yml
	docs/_includes/components/alerts.html
	docs/_includes/components/badges.html
	docs/_includes/components/button-dropdowns.html
	docs/_includes/components/button-groups.html
	docs/_includes/components/dropdowns.html
	docs/_includes/components/glyphicons.html
	docs/_includes/components/input-groups.html
	docs/_includes/components/labels.html
	docs/_includes/components/media.html
	docs/_includes/components/navbar.html
	docs/_includes/components/navs.html
	docs/_includes/components/pagination.html
	docs/_includes/components/panels.html
	docs/_includes/components/progress-bars.html
	docs/_includes/css/buttons.html
	docs/_includes/css/forms.html
	docs/_includes/css/grid.html
	docs/_includes/css/helpers.html
	docs/_includes/css/images.html
	docs/_includes/css/less.html
	docs/_includes/css/responsive-utilities.html
	docs/_includes/css/sass.html
	docs/_includes/css/tables.html
	docs/_includes/css/type.html
	docs/_includes/getting-started/accessibility.html
	docs/_includes/getting-started/browser-device-support.html
	docs/_includes/getting-started/community.html
	docs/_includes/getting-started/download.html
	docs/_includes/getting-started/examples.html
	docs/_includes/getting-started/whats-included.html
	docs/_includes/js/affix.html
	docs/_includes/js/alerts.html
	docs/_includes/js/buttons.html
	docs/_includes/js/carousel.html
	docs/_includes/js/collapse.html
	docs/_includes/js/dropdowns.html
	docs/_includes/js/modal.html
	docs/_includes/js/overview.html
	docs/_includes/js/tabs.html
	docs/_includes/nav/components.html
	docs/_includes/nav/css.html
	docs/_includes/nav/javascript.html
	docs/_includes/nav/main.html
	docs/about.html
	docs/assets/css/docs.min.css
	docs/assets/js/customize.min.js
	docs/assets/js/raw-files.min.js
	docs/dist/css/bootstrap-theme.css
	docs/dist/css/bootstrap-theme.min.css
	docs/dist/css/bootstrap.css
	docs/dist/css/bootstrap.css.map
	docs/dist/css/bootstrap.min.css
	docs/dist/fonts/glyphicons-halflings-regular.eot
	docs/dist/fonts/glyphicons-halflings-regular.svg
	docs/dist/fonts/glyphicons-halflings-regular.ttf
	docs/dist/fonts/glyphicons-halflings-regular.woff
	docs/examples/carousel/index.html
	docs/examples/navbar-fixed-top/index.html
	docs/examples/navbar-static-top/index.html
	docs/examples/navbar/index.html
	docs/examples/non-responsive/index.html
	docs/examples/non-responsive/non-responsive.css
	docs/examples/sticky-footer-navbar/index.html
	docs/examples/theme/index.html
	fonts/glyphicons-halflings-regular.eot
	fonts/glyphicons-halflings-regular.svg
	fonts/glyphicons-halflings-regular.ttf
	fonts/glyphicons-halflings-regular.woff
	less/_carousel.less
	less/_forms.less
	less/glyphicons.less

docs/components/helpers.md

@@ -20,6 +20,10 @@ Convey meaning through color with a handful of emphasis utility classes. These m
   <h4>Dealing with specificity</h4>
   <p>Sometimes emphasis classes cannot be applied due to the specificity of another selector. In most cases, a sufficient workaround is to wrap your text in a <code>&lt;span&gt;</code> with the class.</p>
 </div>
+<div class="bs-callout bs-callout-warning">
+  <h4>Conveying meaning to assistive technologies</h4>
+  <p>Using color to add meaning only provides a visual indication, which will not be conveyed to users of assistive technologies – such as screen readers. Ensure that information denoted by the color is either obvious from the content itself (the contextual colors are only used to reinforce meaning that is already present in the text/markup), or is included through alternative means, such as additional text hidden with the <code>.sr-only</code> class.</p>
+</div>
 
 ### Contextual backgrounds
 
@@ -38,6 +42,11 @@ Similar to the contextual text color classes, easily set the background of an el
   <p>Sometimes contextual background classes cannot be applied due to the specificity of another selector. In some cases, a sufficient workaround is to wrap your element's content in a <code>&lt;div&gt;</code> with the class.</p>
 </div>
 
+<div class="bs-callout bs-callout-warning">
+  <h4>Conveying meaning to assistive technologies</h4>
+  <p>As with <a href="#helper-classes-colors">contextual colors</a>, ensure that any meaning conveyed through color is also conveyed in a format that is not purely presentational.</p>
+</div>
+
 ### Close icon
 
 Use a generic close icon for dismissing content like modals and alerts. **Be sure to include screen reader text when you can** as we've done with `.sr-only`.