Preserve colors for child processes

`stdio` was only used for win32. However the original NodeJS docs allow to use it everywhere http://nodejs.org/api/child_process.html#child_process_child_process_spawn_command_args_options
Checked: it perfectly works on Mac.
I cannot get `[TypeError: Cannot call method 'on' of null]` with `steroids make` on this code. Or this bug is on Win32 only?