Do not listen to mouse events on touch device

This prevents issue #2 from happening on smartphone but does not fix it.
Indeed, we do not want to prevent mouse events on devices that support
both touch and mouses (touch screen on laptop for example).

elm-pep.js

@@ -5,20 +5,23 @@
 
 if (! ("PointerEvent" in window) ) {
 
-	addMouseToPointerListener( document, 'mousedown', 'pointerdown' )
-	addMouseToPointerListener( document, 'mousemove', 'pointermove' )
-	addMouseToPointerListener( document, 'mouseup', 'pointerup' )
+	// Create Pointer polyfill from mouse events only on non-touch device
+	if (! ("TouchEvent" in window) ) {
+		addMouseToPointerListener( document, 'mousedown', 'pointerdown' )
+		addMouseToPointerListener( document, 'mousemove', 'pointermove' )
+		addMouseToPointerListener( document, 'mouseup', 'pointerup' )
 
-	function addMouseToPointerListener( target, mouseType, pointerType ) {
-		target.addEventListener( mouseType, ( mouseEvent ) => {
-			const elmPepTarget = findElmPEP( mouseEvent.target )
-			if ( elmPepTarget !== null ) {
-				let pointerEvent = new MouseEvent( pointerType, mouseEvent )
-				pointerEvent.pointerId = 1
-				pointerEvent.isPrimary = true
-				elmPepTarget.dispatchEvent( pointerEvent )
-			}
-		})
+		function addMouseToPointerListener( target, mouseType, pointerType ) {
+			target.addEventListener( mouseType, ( mouseEvent ) => {
+				const elmPepTarget = findElmPEP( mouseEvent.target )
+				if ( elmPepTarget !== null ) {
+					let pointerEvent = new MouseEvent( pointerType, mouseEvent )
+					pointerEvent.pointerId = 1
+					pointerEvent.isPrimary = true
+					elmPepTarget.dispatchEvent( pointerEvent )
+				}
+			})
+		}
 	}
 
 	addTouchToPointerListener( document, 'touchstart', 'pointerdown' )