Comment 7 for bug 1322473

Done some more digging - although add_objective is called at the Player object, it is actually a property of the map and not the player. I don't want to touch this with a bargepole right now, so I'm proposing my branch for merging.

In case somebody will tackle this later, the Lua scripts to take care of are:

- win condition scripts
- MP and SP scenarios
- campaigns