Cleanup on exit

I started investigating fixing this bug orbital#21 (closed) @jackpot51 , but the recent fixes to not tab thru the default windows seems to hide it.

I will try to use logging or something to investigate further, confirming those windows are still there. To cleanup well, I assume that Orbital would need to be informed of the death of any process it is drawing a window for? Not sure how best to do that in redox? Any ideas

Meanwhile, I did a bit of a cleanup on orbutils/launcher as I worked on it and that is what is here so far.

• I added logging
• I switched all println!() to use logging framework
• I confirmed that the processes are killed and added logging for that.
• I handled errors in startup of logging and the launcher bar
• I removed calls to wait(0) that were causing panics

I have since confirmed orbital#21 (closed) can be reproduced unrelated to login window and maybe a kernel bug.

So, I submit this small clean-up as-is for merging, IF removing that wait(0) stuff at the end looks OK.