Add variables for toggle :before states

They are useful if you want to localize the strings.

sass/toggles.scss

@@ -36,7 +36,7 @@
     color: #999;
     font-size: 13px;
     text-transform: uppercase;
-    content: "Off";
+    content: $toggle-before;
   }
 
   // Active state for toggle
@@ -52,7 +52,7 @@
       right: auto;
       left: 15px;
       color: #fff;
-      content: "On";
+      content: $toggle-active-before;
     }
   }
   // Hide the checkbox

sass/variables.scss

@@ -45,6 +45,13 @@ $card-bg: #fff;
 $button-font-size: 12px;
 
 
+// Toggles
+// --------------------------------------------------
+
+$toggle-before:         "Off";
+$toggle-active-before:  "On";
+
+
 // Transitions
 // --------------------------------------------------