That way, when a function is changed the compiler will tell us about
any matching change we may need to make to WorldGameControlBackend.
Otherwise, the override function that may be present in the world version
may shift to overridding the adapter function.
It's also just cleaner to move these adapter functions to their own class.
git-svn-id: svn+ssh://src.earth.threerings.net/vilya/trunk@187 c613c5cb-e716-0410-b11b-feb51c14d237
Ray Greenwell