coolpi 4b board power key support

[大法师]

When system (like ubuntu desktop) is running, we can press power key to poweroff system or restart system.

if want to skip select option, you can set in the terminal shell:

coolpi@coolpi:~$ gsettings set org.gnome.settings-daemon.plugins.power power-button-action interactive

coolpi@coolpi:~$ gsettings set org.gnome.SessionManager logout-prompt false