jb: option to draw debug graphics to show touch interactions (#797)

## Link to GitHub Issue or related Pull Request, if one exists
related to #697 

## Description of change
Add a new option that paints touch targets and touch points for jubeat;
gets enabled if there is a touch screen connected. This is to help
explain / debug issues when users have their touch screen issues, which
is usually due to misalignment.

Fix the touch targets being off by 1 pixel (center gap is 1px wider in
both directions).

Also, simplify the `improved` algorithm to simulate a finger and trigger
nearest-neighbor for the AC dimensions. In terms of touch performance
this is near identical to what we had before, but it allows us to draw a
nice debug overlay instead of just grids.

## Testing
Tested portrait and landscape versions of jb.

src/spice2x/games/jb/jb.h

@@ -1,20 +1,10 @@
 #pragma once
 
 #include "games/game.h"
+#include "games/jb/jb_touch.h"
 
 namespace games::jb {
 
-    enum JubeatTouchAlgorithm {
-        Legacy,
-        Improved,
-        AcAccurate
-    };
-
-    // touch stuff
-    extern JubeatTouchAlgorithm TOUCH_ALGORITHM;
-    extern bool TOUCH_STATE[16];
-    void touch_update();
-
     class JBGame : public games::Game {
     public:
         JBGame();