makefile: do not overwrite config.php at destination

instead, install config-sample.php; the user will have to
create config.php manually on first install
scoreboard: bugfix, fix broken SQL query
scoreboard: adjust to new encoding of game player information
schema: upgrade from v1 to v2

adds Game_Definition table
game_def: create a link for creating a new game definition
game def: allow creating and changing a game definition
game def: implement 'delete', and take care of contest's game properties

when creating or deleting a game definition in a single-game tournament,
update contests to select the game