Bug fix: no
Feature addition: yes
BC break: no
Symfony2 test pass: yes, but some tests had to be modified
Now all error messages goes to stdout, we cannot separate error
from normal behaviour, this enables writing to stderr stream,
so scripts ran e.g. from cron, can benefit from this well known concept.
There are 2 much nicer implememntations, but:
1) First requires to break the `@api` tagged interfaces.
2) Second requires rewrite of `execute` command declatarion all commands in bundles.
