[bug] echo(content).to(file) also sends content to stdout

[MisterTicot]

Node version (or tell us if you're using electron or some other framework):

v10.15.2

ShellJS version (the most recent version/Github branch you see the bug on):

0.8.3

Operating system:

Ubuntu 19.04

Description of the bug:

echo(content).to(file) also sends content to stdout. If .to(file) is meant to act like >, then it should capture the output rather than copy it to file (like tee would do).

Example ShellJS command to reproduce the error:

shell.echo("foo").to("bar")

[nfischer]

This is a duplicate of issue #146; my hope was that #800 would address this elegantly, but we've made no progress on that issue. Nonetheless, closing this as a duplicate.