feature request: pass initial environment to forked commands

[e2]

[UPDATED]

Problem: Guard::RSpec runs RSpec as a child process with a modified environment, but Zeus doesn't pass the environment variable (due to forking the server without the environment variable and running RSpec with that env).

Ugly workaround: creating a custom Zeus plan setting the variable manually

Preferred solution: Zeus should pass the initial environment to the forked process, since RSpec formatters could be using environment variables.