Merge branch 'kn/cat-file-literally'

Add the "--allow-unknown-type" option to "cat-file" to allow inspecting loose objects of an experimental or a broken type. * kn/cat-file-literally: t1006: add tests for git cat-file --allow-unknown-type cat-file: teach cat-file a '--allow-unknown-type' option cat-file: make the options mutually exclusive sha1_file: support reading from a loose object of unknown type