Song Folder Update

- added folder based custom song/chart handling

this means you can now share custom songs among other players, and easily make custom songs from scratch in game

- fixed combo system to actually be reliable

- made input timing independent of framerate

- made challenge counter reset on miss

- you can flip the accuracy visualiser early/late positioning

- you can place notes without snapping using the alt key

- added a menu to add custom songs easily in game

- added a menu to edit song bpm and offset 

- improved song and chart selection behavior

- fixed loop alignment of chart patterns with respect to song loop

- added ability to turn off perfect scores from showing

- added query before deletion of any kind