Windows: Write verbose output into parent console

Don't open a new console window for verbose output if we got
launched from a console already, but attach to the parent
console.

This allows users to e.g. pipe the verbose output to a file.

Change-Id: Ie602bdd18ef48b576e4b90806541709394882735
Reviewed-by: Niels Weber <niels.weber@digia.com>
Reviewed-by: Karsten Heimrich <karsten.heimrich@digia.com>