Add a prompt before rebooting

[sirtet]

Running the install script, i was shocked by the sudden reboot. I thought it was a crash.

I think it would be nice to have a message like
"Installation successful. Press ENTER to reboot to finish the process".

[sirtet]

Seems this would be in 5-install-drush.sh between line 44 and 45, something like
read -p "Almost done. Press ENTER to reboot to finish the process"