Add "ps" command; either new, or alias to "threads"

[prakashsurya]

While looking at a kernel core dump, I wanted to look at all the processes that may have been running at the time of the crash. My first instinct was to run "ps", but that command doesn't exist. I eventually found the "threads" command, which is exactly what I needed, but took me a little while longer to find the command.

Feel free to close if this goes against the design of "threads", but it may be more user-friendly (at least for me) to have a "ps" command since that is the first thing that I tried.

[sdimitro]

I think having ps is a good idea for people that don't know about threads to start from somewhere - it could even be a layer build on top threads (instead of just an alias) that makes it more process-centric and group tasks that have the same PID together.