Support the network listening mode of Listen

Listen 2.5 now supports listening to file change events over the
network. This adds that option as guard -o '10.0.2.2'
Revert 055c8da..0924650

This rolls back to commit 055c8da9bf593163289bf84327735ec26a9a1f2e.
Revert "Revert 055c8da..0924650"

This reverts commit 7e7a87996c85cf5bb127ad63999be45a173fce96.