Handle edge cases

[sharkdp]

• Very large files => make sure that line number output looks okay
• Binary files => do not attempt to output anything. Instead, print some statistics?
• Lines with no line-ending => Indicate this in a similar way to cat(1)?
• Lines with wrong faulty Unicode characters => print �
• Filenames which are non-UTF8 compatible
• different line ending formats (\n, \r, etc.)

[sharkdp]

Let's ignore point (1) for now and close this ticket. Should it come up again, we can open a new ticket.