Update Zeppelin shell scripts

I suggest Zeppelin use a consistent shell styleguide to make code easier to read\understand and less bug-prone.
I don't understand the difference why firefox process need nohup but Zeppelin is not. I think i need more understanding.

The script 'zeppelin-daemon.sh' is just ordinary shell script. it does not provide any magical demonize feature for standard process. so can you tell me more detail about why 'Zeppelin' or 'Zeppelin deamon script' is deamon and does not need nohup?