* Set "Ctrl+Shift+S" as shortcut for "Save as..." in CvPcb and PCBnew.

This seems to me like the defacto standard for this menu command.
* Added a default filename for save as. Currently it's set to
  "Unnamed file" using _() so its translatable.
* Changed the save dialog in PCBnew to use the path of the "original"
  file as a base for the new file.

cvpcb/menubar.cpp

@@ -95,7 +95,7 @@ void CVPCB_MAINFRAME::ReCreateMenuBar()
     // Save as the .cmp file
     AddMenuItem( filesMenu,
                  wxID_SAVEAS,
-                 _( "Save &As..." ), SAVE_AS_HLP_MSG, KiBitmap( save_xpm ) );
+                 _( "Save &As...\tCtrl+Shift+S" ), SAVE_AS_HLP_MSG, KiBitmap( save_xpm ) );
 
     // Separator
     filesMenu->AppendSeparator();