Merge lp://staging/~bruno-braga/terminator/suppress-multiple-terminals-dialog into lp://staging/terminator/trunk

I was thinking about doing this for years already, and finally had the time to take a look in Terminator's code to implement it. The gnome-terminal has similar popup alert message asking "are you sure you want to close this?" when you have many tabs in place. They offered a way out of this alert dialog, for those who do not want to see that every time they close the terminal.Their solution, however, was not that trivial, as you need to go to gconf and change settings yourself and manually.

For terminator case, it is much worse. In principle, because the main feature if offers is to have multiple terminals on screen. This alert message bugged me for long.

Checking the terminator code, I saw no configurations being handled by gconf (to address similar solution to gnome-terminal), so I added another key in the config.py, that will store a bool to indicate whether to display the alert or not. This decision, by the user, will be available when he closes the terminator application with multiple terminals for the first time, where a checkbox with the option "do not show this again" will be available.

It immitates a bit of other applications, so I think it is a good improvement to this application.

I am not an expert in pyGtk, so feel free to do further changes if needed, so this feature can be implemented in future versions of terminator.

Thank you,