Patch Set 1:

I don't really like the current implementation. I've tried to keep things similar to the Ignore-functionality. WorkingTreeIterator#decorateAttributesQuery is rather annoying. Alternatively there could be a stack (similar to C Git) with a fixed top-level element .git/info/attributes. The stack could be initialized by FileTreeIterator and pushes could happen in createSubtreeIterator(). For the pops we would need some new AbstractTreeIterator.dispose() method.