Test getting process output
Do not timeout child processes (fixes #31)
Pass through output from STDERR of sub processes (fixes #33)
Remove GUI feature (refs #35)
* Drop dependency on clue/zenity-react (and its dependencies)
* Remove "gui" command (but leave it intact)
Merge branch 'stderr' into release
Clean up gitignore
Update CHANGELOG.md
Add MIT license file
Update composer meta info
Update README.md
Prepare v0.5.0 release
Merge branch 'release'