[Feature Request] Option to remove blobs and trees

[frakman1]

I've tried running with:
git-draw --hide-reflogs --hide-blobcontent --hide-treecontent --hide-refs --hide-index --image-only
but still end up with the tree and blob objects. Using the --hide-objects removes the commit objects which is really all I want. Is there a way to keep the commits but hide these: