Large mouse events refactoring and cleanup

js/input/UDragScroll.js

@@ -0,0 +1,18 @@
+import UDrag from "./UDrag"
+
+export default class UDragScroll extends UDrag {
+
+    dragTo(e) {
+        const mousePosition = this.snapToGrid(e.clientX, e.clientY)
+
+        // How far the mouse has been moved
+        const dx = mousePosition[0] - this.mousePosition[0]
+        const dy = mousePosition[1] - this.mousePosition[1]
+
+        this.blueprint.scrollDelta([-dx, -dy])
+
+        // Reassign the position of mouse
+        this.mousePosition = mousePosition
+    }
+
+}