Refactor icon lists heavily

* Icon list now uses a filesystem watcher for updates
* Icon folder is user-customizable
* All the little details. ALL OF THEM.

gui/dialogs/SettingsDialog.h

@@ -55,8 +55,11 @@ slots:
 
 	void on_lwjglDirBrowseBtn_clicked();
 
+
 	void on_jsonEditorBrowseBtn_clicked();
 
+	void on_iconsDirBrowseBtn_clicked();
+
 	void on_maximizedCheckBox_clicked(bool checked);
 
 	void on_buttonBox_accepted();