Ensure context menus can be called on items w/o market group

Author: DarkFenX

gui/builtinContextMenus/cargoAddAmmo.py

@@ -25,7 +25,7 @@ def display(self, callingWindow, srcContext, mainItem):
         return True
 
     def getText(self, callingWindow, itmContext, mainItem):
-        if mainItem.marketGroup.name == "Scan Probes":
+        if mainItem.marketGroup and mainItem.marketGroup.name == "Scan Probes":
             return _t("Add {0} to Cargo (x8)").format(itmContext)
 
         return _t("Add {0} to Cargo (x1000)").format(itmContext)
@@ -34,7 +34,7 @@ def activate(self, callingWindow, fullContext, mainItem, i):
         fitID = self.mainFrame.getActiveFit()
         typeID = int(mainItem.ID)
 
-        if mainItem.marketGroup.name == "Scan Probes":
+        if mainItem.marketGroup and mainItem.marketGroup.name == "Scan Probes":
             command = cmd.GuiAddCargoCommand(fitID=fitID, itemID=typeID, amount=8)
         else:
             command = cmd.GuiAddCargoCommand(fitID=fitID, itemID=typeID, amount=1000)