Allow for configuration of file sets to be be removed after requirejs bundle

[manuelpichler]

Currently all *.js files within the bundle:commons.srcdir.js are removed after the requirejs bundling has taken place. The file set to be used for removal here should be configurable somehow

[manuelpichler]

Evaluate if this could be done using a fileset reference, which may be overridden using a projects build.xml