Checkbox button debounce (#774)

This fixes: https://github.com/ArthurSonzogni/FTXUI/issues/773

Dragging the mouse with the left button pressed now avoids activating multiple
checkboxes.

Add support for detecting mouse press transition. Added:
```cpp
// The previous mouse event.
Mouse Mouse::previous;

// Return whether the mouse transitionned from:
// released to pressed => IsPressed()
// pressed to pressed => IsHeld()
// pressed to released => IsReleased()
bool Mouse::IsPressed(Button button) const;
bool Mouse::IsHeld(Button button) const;
bool Mouse::IsReleased(Button button) const;
```
A couple of components are now activated when the mouse is pressed,
as opposed to released.

Co-authored-by: ArthurSonzogni <sonzogniarthur@gmail.com>

include/ftxui/component/screen_interactive.hpp

@@ -112,6 +112,7 @@ class ScreenInteractive : public Screen {
 
   bool frame_valid_ = false;
 
+  Mouse latest_mouse_event_;
   friend class Loop;
 
  public: