- 'theano-cache clear' will now delete cache entries containing pickled files
that cannot be unpickled.
- Replaced some manual calls to shutil.rmtree by calls to _rmtree to
standardize cache directory deletion.
- Cache entries associated to KeyData objects whose keys are broken should
now be cleared if the module file is gone.
- More comprehensive cleanup of the entry_from_key, module_hash_to_key_data
and loaded_key_pkl dictionaries when deleting a cache entry.