'Rated+' List Support #279
Description
Add support for adding unrated levels to the demonlist. Keep track of the 'rated' status of demons in a new column on the demons table. On the overview page, give an option to list only rated levels, or rated + unrated levels ('Rated+' list). In both cases, only 150 levels should be listed.
It should get its own stats version of the stats viewer, so all the score caching stuff will need to get duplicated.
Time Machine should just work out of the box mostly, though for the non-rated+ time machine we might have to change the position calculation to be call to RANK() over the result (we'll need that for the normal list already anyway though). Maybe we can have some sort of "would be #XXX including unrated levels" text?