ccs bar now spawns the web-server as a detached background process and
exits immediately instead of hosting it in the foreground, so closing the
terminal no longer takes the bar offline. Adds 'bar serve' (the long-lived
host), 'bar stop', and 'bar status', and records ~/.ccs/bar/launch.json at
install so the app can start the server without a shell PATH.
Refs #1526
Tam Nhu Tran
b5ef06a4d5