jb: touch debounce (#798)

## Link to GitHub Issue or related Pull Request, if one exists
n/a

## Description of change
Debouce option for touch input. Applies to all touch handlers (rawinput,
win8, win7) since it sits at the touch layer, and then consumed by jb
touch logic.

## Testing

src/spice2x/touch/touch.cpp

@@ -20,6 +20,7 @@
 #include "util/detour.h"
 #include "util/libutils.h"
 #include "util/logging.h"
+#include "util/time.h"
 #include "util/utils.h"
 
 #include "handler.h"
@@ -538,6 +539,7 @@ static LRESULT CALLBACK SpiceTouchWndProc(HWND hWnd, UINT msg, WPARAM wParam, LP
                         .x = GET_X_LPARAM(lParam),
                         .y = GET_Y_LPARAM(lParam),
                         .mouse = true,
+                        .down_ms = get_performance_milliseconds(),
                     };
                     TOUCH_POINTS.push_back(tp);
 
@@ -851,6 +853,9 @@ void touch_write_points(std::vector<TouchPoint> *touch_points) {
         // create new touch point when not found
         if (!found) {
 
+            // stamp the landing time so debounce can measure the contact's age
+            tp.down_ms = get_performance_milliseconds();
+
             // add touch point
             TOUCH_POINTS.push_back(tp);