provide property to make a clean clone

I've got a usecase where a plugin generates files which are NOT written to the target-directory.
This means these files won't be removed with a standard clean-goal configured inside the invoker-plugin, so it might (or should) result in failing tests.
Think of the release.properties, only one difference: the release-plugin has it's own clean-goal. But in my case a separate clean-goal is just a bit of overkill. It would be nicer if this could be resolved with the invoker plugin itself.
A patch is attached with the property cloneClean (default false to keep current and optimal behaviour) which will clean the directory if it's already there + an IT.