ContactType: Add a way to clone.

src/ical.js.d.ts

@@ -3,8 +3,12 @@ declare module 'ical.js' {
   class Component {
     name: string;
 
+    static fromString(str: string): Component;
+
     constructor(jCal: Array<any> | string, parent?: Component);
 
+    toJSON(): Array<any>;
+
     getFirstSubcomponent(name?: string): Component | null;
 
     getFirstPropertyValue(name?: string): any;

src/pim-types.tsx

@@ -39,6 +39,10 @@ export class ContactType {
     return this.comp.toString();
   }
 
+  clone() {
+    return new ContactType(new ICAL.Component(this.comp.toJSON()));
+  }
+
   get uid() {
     return this.comp.getFirstPropertyValue('uid');
   }