Update to latest version without redownloading and re-importing the project?

[WorldsEnder]

Is there a way how I could update my project to the latest version of forge with the new gradlew system?

I don't want to redownload everything (how can I know if the assets are still the right ones?) but I don't see the possibility to do that.

Let's put it this way: reimporting the project into Eclipse would be okay but needless redownloads aren't.

If there isn't I would request this feature for future builds/downloads.

If that is not possible, is there a way to clean the gradlew(-temporary) files? Some sort of "gradlew -clean"?

[loordgek]