chocolate-doom: new package

Chocolate Doom is a set of conservative source ports for Doom, Heretic,
Hexen and Strife, with a philosophy of preserving the look, feel, and
bugs of the vanilla versions of each.

http://www.chocolate-doom.org



Signed-off-by: Rodrigo Rebello <rprebello@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>