Add component key to IState

Since beta.1, you can set `component` if you are using Angular 1.5 (component syntax)

angular-ui-router/angular-ui-router.d.ts

@@ -44,6 +44,10 @@ declare namespace angular.ui {
          * Function, returns HTML content string
          */
         templateProvider?: Function | Array<string|Function>;
+        /**
+         * String, component name
+         */
+        component?: string;
         /**
          * A controller paired to the state. Function, annotated array or name as String
          */