[Frontend] Converting tree items and labels to flex-box

open #431
In-progress fixing mobile;
Mostly done, link icon in mobile needs
better positioning;

platform/commonUI/general/res/sass/mobile/_tree.scss

@@ -34,20 +34,20 @@
 		line-height: $mobileTreeItemH;
 		margin-bottom: 0px;
 		.view-control {
-			//@include test(red);
-			position: absolute;
-			font-size: 1.1em;
-			height: $mobileTreeItemH;
-			line-height: inherit;
-			right: 0px;
-			width: $mobileTreeRightArrowW;
-			text-align: center;
+            order: 2;
+            width: $mobileTreeItemH;
+            &.has-children {
+                &:before {
+                    content: "\7d";
+                    left: 50%;
+                    @include transform(translateX(-50%) rotate(90deg));
+                }
+                &.expanded:before {
+                    @include transform(translateX(-50%) rotate(270deg));
+                }
+            }
 		}
-
-		.label,
 		.t-object-label {
-			left: 0;
-			right: $mobileTreeRightArrowW + $interiorMargin; // Allows tree item name to stop prior to the arrow
 			line-height: inherit;
 		}
 	}