Support progress of child processes

[h-bragg]

If a child process outputs a progress bar or progress number, interpret this and display it as a progress bar to the user.

Maybe then support total progress for all processes?

[h-bragg]

When using the table view, you can get it to print the last line from each child process, this would support the process bar.

However there is no interpreting output numbers to be the current progress

[h-bragg]

This is supported when using child pools, they provide a progress. Interpreting the output of an application as a progress is not there yet.