swh-identify CLI should behave like other checksuming tools and output the name of the file being hashed, i.e., instead of:

$ swh-identify hello.c
swh:1:cnt:524175c2bad0b35b975f79284c2f5a6d5eaf2eb4

it should do:

$ swh-identify hello.c
swh:1:cnt:524175c2bad0b35b975f79284c2f5a6d5eaf2eb4    hello.c

Details:

• we should use a \t character as separator between the two fields for friendliness toward *nix filters
• we should have an option to disable printing filename