vat and sgst/cgst tax overlapping changes done

See merge request gnukhata/gkcore!405

Changes done for rejection note.

Closes #388

See merge request gnukhata/gkcore!404

If requested invoice have two product, from that one product completaly rejected then that product cannot be display in frontend.

Fully rejected invoices are not showing in frontend.

Revamp Profit and Loss statement

Closes #383

See merge request gnukhata/gkcore!403

Fetched accounts and calculation. also ignored Profit and loss

groups and accounts whose current balance in 0.00

and grossloss

account, then added account name with its balance in a
dictionary. calculated total of subgroup and calculated total of main
group also and added subgroup with accounts dictionary in main dictionary

Fixed bugs in close books where new accounts were not getting created Also fixed bug in function which gives new organisation orgcode

See merge request gnukhata/gkcore!402

Completed task of roll over without close books and fixed an unrelated bugs.

See merge request gnukhata/gkcore!401

and except