Fix twitchy scrolling on touchpads (#381)

Fix twitchy scrolling on touchpads

include/ALabel.hpp

@@ -36,6 +36,7 @@ class ALabel : public IModule {
 
  private:
   std::vector<int> pid_;
+  gdouble distance_scrolled_;
 };
 
 }  // namespace waybar

include/modules/sway/workspaces.hpp

@@ -41,6 +41,7 @@ class Workspaces : public IModule, public sigc::trackable {
   util::JsonParser                             parser_;
   bool                                         scrolling_;
   std::unordered_map<std::string, Gtk::Button> buttons_;
+  gdouble                                      distance_scrolled_;
 
   util::SleeperThread thread_;
   Ipc                 ipc_;