Changed seafile.sh and seahub.sh to make it more user friendly
1. The scripts will run as the user who owns the file. For example,
   if the file is owned by "www-data" it will run as that user
   if executed as root.
2. The script has init.d headers. On Ubuntu/Debian, it one can
    link to the file in /etc/init.d and then run:
        "update-rc.d install <NAME> defaults"
    This makes it really easy to ensure that seafiles starts and
    stops. Tested on Ubuntu 12.04 and Debian (Rasberry Pi)