delete function modified for invalid_itemcodes
clearstock function modified for null fields
Merge branch 'Pubudu' of https://github.com/Kasunucsc/MotorYardInventory into Kasun

# By pubbzz92
# Via pubbzz92
* 'Pubudu' of https://github.com/Kasunucsc/MotorYardInventory:
  delete function modified for invalid_itemcodes clearstock function modified for null fields