Use grid classes or mixins on .dl-horizontal, update docs to include it, removes auto truncate and makes .text-overflow mixin into a .text-truncate class and mixin combo for better granularity

scss/_utilities.scss

@@ -79,6 +79,7 @@
 .text-center         { text-align: center; }
 .text-justify        { text-align: justify; }
 .text-nowrap         { white-space: nowrap; }
+.text-truncate       { @include text-truncate; }
 
 // Transformation
 .text-lowercase      { text-transform: lowercase; }