CLI utility to pipe JSON logs through to pretty print and colorize them

[themarolt]

Implemented a small utility tool to use when developing an application using zerolog as mentioned in #316.

The only thing that is untested is Windows instructions specifically commands that redirect stderr to stdout:

some_program_with_zerolog 2>&1 | go run cmd/pretty_pipe/pretty_pipe.go

Can someone verify this is working? I only have access to a Linux machine currently.