Add missing/change definitions

durandal/durandal.d.ts
========================
- Make applicationHost parameter optional in setRoot
- Add missing activeRoute definition
- Add missing useConvention definition
- Add missing handleInvalidRoute definition
- Change mapRoute definition so you can pass an URL with all the other
parameters as you will usealy do or you pass a RouteInfo object without
having to give it any other parameter. moduleId, name and visible are
now optional.

toastr/toastr.d.ts
======================
- Add backgroundpositionClass to ToastrOptions interface