Hello, It appears that cwltool no longer allows you to assign a path as a `File`, which then makes it difficult to mount a directory to the docker run. This is especially problematic for things like variant annotation software which often have a particular directory structure containing 100's of annotation files. It seems like the commit present [here](https://github.com/common-workflow-language/cwltool/commit/893de464b3dd6f359e39ee00d8d4f69cfdb1e1bc) is potentially the culprit. This functionality worked with cwl version `1.0.20160129183049` but it definitely doesn't work in the current one. How can we handle this issue?