Code review comment for lp:~widelands-dev/widelands/rework-resource-indicators

OK, refactored the building help so it now queries the highest resi for the given resource from the given TribeDescr and uses its representative_image. The barbarian scenario also uses representative_image for each resi now instead of fixed image paths.
There was no need to define an icon, as representative_image points to the first idle frame by default.