Add null separator support `-0` for `xargs`

[eloyesp]

It would be nice to have a way to handle files with whitespace, find have the -print0 predicate and xargs have the -0 flag to handle that output. Adding that same flag would enable something like:

$ find documents/ -print0 | fzy -0 | xargs -0 xdg-open

Does it makes sense.

[timbsng]

Seems like this has already been implemented with c4524ae and 79e4808. Unfortunately the latest release tag is still prior to those changes, see #147.