All icons are 1px too tall, uses same technique as bootstrap (offset1px on glyphicons)

src/elements/icon.less

@@ -61,6 +61,8 @@ i.icon {
 
   speak: none;
 
+  vertical-align: 1px;
+
   -webkit-box-sizing: border-box;
   -moz-box-sizing: border-box;
   -ms-box-sizing: border-box;