[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/commonUI/general/res/sass/controls/_buttons.scss

@@ -95,10 +95,7 @@ $pad: $interiorMargin * $baseRatio;
 
 .s-icon-btn {
     @extend .ui-symbol;
-    color: $colorBtnIcon;
-    &:hover {
-        color: lighten($colorBtnIcon, $ltGamma);
-    }
+    // Color and styling additionally in _controls.scss
 }
 
 .mini-tab {

platform/commonUI/general/res/sass/controls/_controls.scss

@@ -187,7 +187,8 @@ label.checkbox.custom {
     }
 }
 
-.context-available {
+.context-available,
+.s-icon-btn {
     $c: $colorKey;
     color: $c;
     &:hover {

platform/commonUI/general/res/sass/features/_time-display.scss

@@ -18,13 +18,13 @@
 		&:hover .control {
             margin-right: $interiorMargin;
             opacity: 1;
-			width: auto;
+			width: 1em;
 		}
 	}
 
     .value {
-        color: pullForward($colorBodyFg, 20%);
-        font-weight: 600;
+        color: pullForward($colorBodyFg, 50%);
+        font-weight: 400;
         .direction {
             font-size: 0.8em;
         }