Revert "Revert "Fix potential memory leaks""

This reverts commit 2d33c20231 and
reapplies various patches for memory leaks.
The reason for the revert was a bug for a maximum duration interval
which caused sleep_for() to cause unpredictable behavior.

include/modules/upower/upower.hpp

@@ -69,7 +69,7 @@ class UPower : public AModule {
   UpDevice *displayDevice;
   guint login1_id;
   GDBusConnection *login1_connection;
-  UPowerTooltip *upower_tooltip;
+  std::unique_ptr<UPowerTooltip> upower_tooltip;
   std::string lastStatus;
   bool showAltText;
   bool upowerRunning;

include/modules/upower/upower_tooltip.hpp

@@ -2,6 +2,7 @@
 
 #include <libupower-glib/upower.h>
 
+#include <memory>
 #include <unordered_map>
 
 #include "gtkmm/box.h"
@@ -16,7 +17,7 @@ class UPowerTooltip : public Gtk::Window {
 
   const std::string getDeviceIcon(UpDeviceKind& kind);
 
-  Gtk::Box* contentBox;
+  std::unique_ptr<Gtk::Box> contentBox;
 
   uint iconSize;
   uint tooltipSpacing;