Remove all trailing spaces

No real changes, just clean up sources by removing trailing spaces from
all the non-generated files.

This should hopefully avoid future commits mixing significant changes
with insignificant whitespace ones.

src/qt/menu.cpp

@@ -211,7 +211,7 @@ bool wxMenuBar::Append( wxMenu *menu, const wxString& title )
 
     QMenu *qtMenu = SetTitle( menu, title );
     m_qtMenuBar->addMenu( qtMenu );
-    
+
     return true;
 }