Some files get corrupted after running through the pre-commit

[coltonglasgow]

When committing files like.pdf or .png, the file will become corrupted. If you commit the same files with --no-verify, skipping the pre-commit, the file will not be corrupted. Something in the pre-commit is causing these files to become corrupt.

[rjyounes]

The serializer pre-commit should skip any files that don't have extension .ttl or .owl. It's puzzling that it would then corrupt the file.

[rjyounes]

The problem is in the call to remove_skos_decls after serialize_all, so applies to all files regardless of whether they passed through the serializer or not. This corrupts the binary files. This call is slated for removal in issue #934. I'm going to remove it here, rather than moving the function to apply in the serialize function rather than after it.