Making a custom build of Cesium

I like that Cesium contains a lot of features, but when I'm creating apps I end up using just a few. I would like to create custom builds for my apps, and only include the parts of the library that I use.

What is the best way to create custom builds with Cesium?

Looking at the source, this could be a way forward:
- Create a new app, MyApp, in the Apps-folder.
- Add a new target, buildMyApp in build.xml similar to buildCeciumViewer
- Build with ant ./Tools/apache-ant-1.8.2/bin/ant buildMyApp

Is this the best way forward?

It would be great if we could do this without modifying build.xml, something like:

./Tools/apache-ant-1.8.2/bin/ant buildApp MyApp

Sending MyApp as a parameter to buildApp target. As long as MyApp follows an AMD pattern, ant will build it. I'm more used to Grunt than ant, so I don't know if it's possible.