Log Message:
games: Add jumpnbump. While here, add missing entries to the root Makefile.

This is a game for the whole family. You play cute fluffy little bunnies
and hop on each other's heads.

At the beginning you are in the menu, where you have to let each active
player jump over the tree trunk to enter the play area, and then walk to
the right. You will then enter the arena. The aim is to jump on the other
bunnies' heads...

Jump 'n Bump was originally a DOS game by Brainchild Design, which was open
sourced under the GPL license and ported to SDL, and then SDL2.

It's a true multiplayer game, you can't play this alone. It has network
support.