950f2c84a3
New code shall be more easy to maintain and extend. Sorting is now handled quite the same as filtering, and all filtering parameters are now packed into a sub-struct to help extending it later. Also done some optimizations in filelist refresh, and sorting/filtering area. Now we should avoid re-sorting and re-filtering too often, also removed calls to those in read_xxx funcs. Note thumbnail job is still started basically on each call to `file_refresh()`, will be addressed in next commit.