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/source/ui/error_box.cpp

@@ -1134,10 +1134,6 @@ auto ErrorBox::Update(Controller* controller, TouchInfo* touch) -> void {
     Widget::Update(controller, touch);
 }
 
-auto ErrorBox::OnLayoutChange() -> void {
-
-}
-
 auto ErrorBox::Draw(NVGcontext* vg, Theme* theme) -> void {
     gfx::dimBackground(vg);
     gfx::drawRect(vg, m_pos, theme->elements[ThemeEntryID_SELECTED].colour);