add touch support (#77)

* initial work on touch support

* add touch support to all objects

* add touch scrolling, fix scrollbar, fix appstore search

- when fireing an action, the action array may change. so the loop should break early as soon as an action is handled.
  this fixes the appstore search when pressing B.
- scrollbar no longer goes oob. fixes #76

currently, scrolling has no acceleration.

sphaira/include/ui/error_box.hpp

@@ -10,7 +10,6 @@ public:
     ErrorBox(Result code, const std::string& message);
 
     auto Update(Controller* controller, TouchInfo* touch) -> void override;
-    auto OnLayoutChange() -> void override;
     auto Draw(NVGcontext* vg, Theme* theme) -> void override;
 
 private: