fix(ie): Add SVG contains polyfill (#575)

Author: Mingze

src/BoxAnnotations.ts

@@ -1,3 +1,4 @@
+import './polyfill';
 import getProp from 'lodash/get';
 import BaseAnnotator from './common/BaseAnnotator';
 import ImageAnnotator from './image/ImageAnnotator';

src/polyfill.ts

@@ -0,0 +1,19 @@
+// Add support for SVGElement.contains in IE11
+if (!SVGElement.prototype.contains) {
+    Object.defineProperty(SVGElement.prototype, 'contains', {
+        configurable: true,
+        enumerable: false,
+        writable: true,
+        value: function contains(node: Node) {
+            let n: Node | null = node;
+            do {
+                if (this === n) {
+                    return true;
+                }
+                n = n && n.parentNode;
+            } while (n);
+
+            return false;
+        },
+    });
+}