Make TaskMarks clickable and jump to the right task in the taskwindow

That means it is no longer possible to make bookmarks on lines with
errors or warnings by simply clicking. That's not nice.
It might be better to do something different, but let's see how the
feedback to this is.

Change-Id: I34788ff638ed49c21001d03cd60f992ffabd6153
Reviewed-by: hjk <qthjk@ovi.com>
Reviewed-by: Eike Ziller <eike.ziller@nokia.com>

src/plugins/projectexplorer/taskwindow.h

@@ -90,6 +90,7 @@ private slots:
     void addTask(const ProjectExplorer::Task &task);
     void removeTask(const ProjectExplorer::Task &task);
     void updatedTaskLineNumber(unsigned int id, int line);
+    void showTask(unsigned int id);
     void clearTasks(const Core::Id &categoryId);
     void setCategoryVisibility(const Core::Id &categoryId, bool visible);