[New Feature] copy multi records from Excel, paste into child table directly

@szufisher, I have been using this from last two days. Works awesome. Following are my observations after using it, please see how they can be taken care of.

  1. In your barcode feature, [New Feature Proposal]Barcode scan to create/update records in child table, useful for stock movement and orders - #10 by rishinikhil, the item qty gets increased upon repeat. But when we copy the table here, it does not.
    Now , if the code is not made that way, then its perfectly fine, let it be as is.

  2. Speed - The page becomes unresponsive or it takes time after adding around 50-80 items. What I do is - save invoice, hard refresh and then again paste the remaining items.