Add new border utils

- Move and rename .img-rounded to .rounded, .img-circle to .rounded-circle
- Add new .rounded-{direction} utils
- New docs pages for border utils with TBD comments for the border property
- Removes most image examples for rounding from the content/images docs in favor of new docs page

docs/_data/nav.yml

@@ -55,6 +55,7 @@
 
 - title: Utilities
   pages:
+    - title: Borders
     - title: Clearfix
     - title: Close icon
     - title: Colors

docs/content/images.md

@@ -29,19 +29,15 @@ Images in Bootstrap are made responsive with `.img-fluid`. `max-width: 100%;` an
 In Internet Explorer 9-10, SVG images with `.img-fluid` are disproportionately sized. To fix this, add `width: 100% \9;` where necessary. This fix improperly sizes other image formats, so Bootstrap doesn't apply it automatically.
 {% endcallout %}
 
-## Image shapes
+## Image thumbnails
 
-Add classes to an `<img>` element to easily style images in any project.
+In addition to our [border-radius utilities]({{ site.baseurl }}/utilities/borders/), you can use `.img-thumbnail` to give an image a rounded 1px border appearance.
 
 <div class="bd-example bd-example-images">
-  <img data-src="holder.js/200x200" class="rounded" alt="A generic square placeholder image with rounded corners">
-  <img data-src="holder.js/200x200" class="img-circle" alt="A generic square placeholder image where only the portion within the circle circumscribed about said square is visible">
   <img data-src="holder.js/200x200" class="img-thumbnail" alt="A generic square placeholder image with a white border around it, making it resemble a photograph taken with an old instant camera">
 </div>
 
 {% highlight html %}
-<img src="..." alt="..." class="rounded">
-<img src="..." alt="..." class="img-circle">
 <img src="..." alt="..." class="img-thumbnail">
 {% endhighlight %}
 

docs/utilities/borders.md

+---
+layout: docs
+title: Borders
+group: utilities
+---
+
+Use border utilities to quickly style the `border` and `border-radius` of an element. Great for images, buttons, or any other element.
+
+## Border-radius
+
+Add classes to an element to easily round its corners.
+
+<div class="bd-example bd-example-images">
+  <img data-src="holder.js/100x100" class="rounded" alt="Example rounded image">
+  <img data-src="holder.js/100x100" class="rounded-top" alt="Example top rounded image">
+  <img data-src="holder.js/100x100" class="rounded-right" alt="Example right rounded image">
+  <img data-src="holder.js/100x100" class="rounded-bottom" alt="Example bottom rounded image">
+  <img data-src="holder.js/100x100" class="rounded-left" alt="Example left rounded image">
+  <img data-src="holder.js/100x100" class="rounded-circle" alt="Completely round image">
+</div>
+
+{% highlight html %}
+<img src="..." alt="..." class="rounded">
+<img src="..." alt="..." class="rounded-top">
+<img src="..." alt="..." class="rounded-right">
+<img src="..." alt="..." class="rounded-bottom">
+<img src="..." alt="..." class="rounded-left">
+<img src="..." alt="..." class="rounded-circle">
+{% endhighlight %}

scss/_images.scss

@@ -9,10 +9,6 @@
   @include img-fluid();
 }
 
-// Rounded corners
-.rounded {
-  @include border-radius($border-radius-lg);
-}
 
 // Image thumbnails
 .img-thumbnail {
@@ -27,11 +23,6 @@
   @include img-fluid(inline-block);
 }
 
-// Perfect circle
-.img-circle {
-  border-radius: 50%;
-}
-
 //
 // Figures
 //

scss/_utilities.scss

 @import "utilities/background";
+@import "utilities/borders";
 @import "utilities/clearfix";
 @import "utilities/display";
 @import "utilities/flex";

scss/utilities/_borders.scss

+//
+// Border-width
+//
+
+// TBD...?
+
+
+//
+// Border-radius
+//
+
+.rounded {
+  @include border-radius($border-radius);
+}
+.rounded-top {
+  @include border-top-radius($border-radius);
+}
+.rounded-right {
+  @include border-right-radius($border-radius);
+}
+.rounded-bottom {
+  @include border-bottom-radius($border-radius);
+}
+.rounded-left {
+  @include border-left-radius($border-radius);
+}
+
+.rounded-circle {
+  border-radius: 50%;
+}