Fixes: Improved sidebar looks and layout

Details:
-Centered all the text labels.
-Added shadow on title text.
-Made progressbar go all the way and placed the button on top.
-Added some spacing between warning and error icons.
-Improved cosmetics on progress bar itself.

src/plugins/coreplugin/progressmanager/progresspie.h

@@ -49,6 +49,7 @@ public:
     bool hasError() const;
     QSize sizeHint() const;
     void paintEvent(QPaintEvent *);
+    void mouseMoveEvent(QMouseEvent *);
 
 signals:
     void clicked();