[Frontend] Tweaks to slider knobs

open #889
- Knob size increased;
- Knob grippies added;

platform/commonUI/general/res/sass/_mixins.scss

@@ -139,6 +139,17 @@
     background-size: $d $d;
 }
 
+@mixin bgStripes($c: yellow, $a: 0.1, $bgsize: 5px, $angle: 90deg) {
+    @include background-image(linear-gradient($angle,
+        rgba($c, $a) 25%, transparent 25%,
+        transparent 50%, rgba($c, $a) 50%,
+        rgba($c, $a) 75%, transparent 75%,
+        transparent 100%
+    ));
+    background-repeat: repeat;
+    background-size: $bgsize $bgsize;
+}
+
 @mixin bgVertStripes($c: yellow, $a: 0.1, $d: 40px) {
     @include background-image(linear-gradient(-90deg,
         rgba($c, $a) 0%, rgba($c, $a) 50%,

platform/commonUI/general/res/sass/controls/_time-controller.scss

@@ -147,6 +147,16 @@
 
 	.knob {
 		z-index: 2;
+        &:before {
+            $mTB: 2px;
+            $grippyW: 3px;
+            $mLR: ($sliderKnobW - $grippyW)/2;
+            @include bgStripes($c: pullForward($sliderColorKnob, 20%), $a: 1, $bgsize: 4px, $angle: 0deg);
+            content: '';
+            display: block;
+            position: absolute;
+            top: $mTB; right: $mLR; bottom: $mTB; left: $mLR;
+        }
 		.range-value {
 			@include trans-prop-nice-fade(.25s);
             font-size: 0.7rem;
@@ -193,6 +203,8 @@
 	padding: 1px 1px 0 $interiorMargin;
 }
 
+/******************************************************************** MOBILE */
+
 @include phoneandtablet {
 	.l-time-controller, .l-time-range-inputs-holder {
 		min-width: 0px;