Pass only host to applescript

[otakustay]

Pass only host to applescript

[michaellzc]

@otakustay I think this is a legit use case.

Since this is a new behaviour, users should opt-in to use this new feature.

For the sake of keeping the interface consistent with open, instead of adding a new attribute to options, we can use an environment variable to control this behaviour, i.e

// open.js
require('better-opn')('http://localhost:3000/login')

# The env var name is tentative. I am opened to any better name
$ OPEN_MATCH_HOST_ONLY=true node open.js

Are you opened to contribute?