resolves #117

- adds a new group for total assigned skilled labors. this excludes both
hauling and other skill-less labors like recovering wounded
- updated the custom profession/superlabor labors list to put skill-less
labors at the bottom, as opposed to only hauling labors
- updated the script method for total_assigned_labors to exclude
skill-less labors, instead of only hauling if the flag was set