Removes bottom status bar.

StatusBar class calls are commented out and replaced with notifications.
SlicicingProgress notification shows progress of slicing, ProgressIndicator notification handles other progress information, like arrange objects etc.

src/slic3r/GUI/ProgressStatusBar.hpp

@@ -25,6 +25,7 @@ namespace Slic3r {
  * of the Slicer main window. It consists of a message area to the left and a
  * progress indication area to the right with an optional cancel button.
  */
+ 
 class ProgressStatusBar : public ProgressIndicator
 {
     wxStatusBar *self;      // we cheat! It should be the base class but: perl!