fix etag cache not being returned upon the 2nd request, add jump page support for all menus.

- all menus feature page jumping, using L2/R2 (or DPAD_LEFT/DPAD_RIGHT in list menus)
- successive calls to fetch the etag would fail, this was seen in themezer and github menus.
- add limit the number of icons loaded per frame in homebrew menu.
- display default icon the image is not ready to be loaded / invalid.

fixes #53

sphaira/include/ui/menus/menu_base.hpp

@@ -21,6 +21,9 @@ struct MenuBase : Widget {
     void SetTitleSubHeading(std::string sub_heading);
     void SetSubHeading(std::string sub_heading);
 
+    static auto ScrollHelperDown(u64& index, u64& start, u64 step, s64 row, s64 page, u64 size) -> bool;
+    static auto ScrollHelperUp(u64& index, u64& start, s64 step, s64 row, s64 page, s64 size) -> bool;
+
 private:
     void UpdateVars();
 

sphaira/include/ui/types.hpp

@@ -359,7 +359,7 @@ struct Controller {
         m_kup = 0;
     }
 
-    void UpdateButtonHeld(HidNpadButton buttons) {
+    void UpdateButtonHeld(u64 buttons) {
         if (m_kdown & buttons) {
             m_step = 50;
             m_counter = 0;
@@ -367,7 +367,7 @@ struct Controller {
             m_counter += m_step;
 
             if (m_counter >= m_MAX) {
-                m_kdown |= buttons;
+                m_kdown |= m_kheld & buttons;
                 m_counter = 0;
                 m_step = std::min(m_step + 50, m_MAX_STEP);
             }