Made it possible to use TypeScript class as a controller

mithril.d.ts

@@ -83,16 +83,19 @@ interface MithrilEvent {
 }
 
 interface MithrilController {
-       (): any;
        onunload?(evt: Event): any;
 }
 
+interface MithrilControllerFunction extends MithrilController {
+       (): any;
+}
+
 interface MithrilView<T extends MithrilController> {
        (ctrl: T): string|MithrilVirtualElement;
 }
 
 interface MithrilModule<T extends MithrilController> {
-       controller: T;
+       controller: MithrilControllerFunction|{ new(): T };
        view: MithrilView<T>;
 }