It's the classic connect4. You have to connect 4 lines in a row.
	You play against the computer.
	The IA code comes from the project 4stattack by Jeroen Vloothuis
	http://forcedattack.sourceforge.net/
	It's the first commit and it's a work in progress.

	Bruno reviewed all key_press return value like explained here:

	It doesn't explain us why we get event twice but at least we know what
	has changed. Anyway, the return value in all key_press function of each
	plugins are not well set. We should return:
	TRUE  = We handled the key
	FALSE = We did not handled the key, gtk need to send it to next widget