Redirection of channels handled by QProcess

If you think about it, the outputs of all ForwardedChannels are merged into a common sink - the parent process' console (or session log file). Unfortunately, this is not possible for channels handled by QProcess.

It would be usefull to be able to do the following:

1. shell: foo > bar.txt 2>&1
   QProcess proc;
   proc.setStandardOutputFile( "/bar.txt" );
   proc.setStandardErrorSink( &proc, QProcess::OutputHandle );