controller.Base: onConstructed() => pass the old hash value

this would be a very useful enhancement for controllers, which get created at run-time, where a hash-change has already happened. we need to delay this one a bit though, since it would have a pretty big impact on our current client-project, which needs to get prepared for the change first.

old code:

currentHash && this.onHashChange(currentHash, null);

new code:

currentHash && this.onHashChange(currentHash, HashHistory.second());