Feature request: ability to toggle case fold in swiper #259

As far as I can tell, whether or not to toggle case fold in swiper is not configurable: if your query is all lowercase you always get case folding; if it is not all lowercase, you never get case folding. Very rarely I want to do a case sensitive search for a lowercase query with swiper, is there any way of getting that now? If not, how about adding that feature?