[Frontend] Final cleanups, tweaks; Refactored s-icon-btn

open #208
Unit tested in both themes;
.s-icon-btn refactored slightly to focus on usage
as an icon-only element, removed overlap designations
with .s-btn in markup;
Colors normalized for theming;
Code cleanup;

platform/forms/res/templates/controls/color.html

@@ -20,7 +20,7 @@
  at runtime from the About dialog for additional information.
 -->
 <div
-	class="t-btn l-btn s-btn s-icon-btn s-menu-btn menu-element t-color-palette"
+	class="t-btn l-btn s-btn s-menu-btn menu-element t-color-palette"
     ng-controller="ClickAwayController as toggle"
 	>