Make seattle start automatically on system startup

[XuefengHuang]

Instead of creating a crontab @reboot, I add a function to create an init.d start script at installation on OpenWrt firmware. These are my test result:

root@OpenWrt:~/sea-min# ./install.sh --percent 100
Seattle is being installed on a OpenWrt firmware.
System benchmark starting...
Benchmark complete and vessels created!
Preparing Seattle to run automatically at startup...
Seattle is setup to run at startup!
Generating the Node Manager RSA keys.  This may take a few minutes...
Keys generated!
Starting seattle...
seattle has been started: Wed Jun 24 18:50:11 UTC 2015
seattle has been installed!
To learn more about useful, optional scripts related to running seattle, see the README file.
root@OpenWrt:~/sea-min# ./uninstall.sh
Seattle has been successfully uninstalled.  It is now safe to remove all Seattle files and directories from your system.