Add sale comment to POS serialization
Merge pull request #14 from GauravButola/develop

Add sale comment to POS serialization
Merge pull request #13 from GauravButola/feature/round-down-5684

Add and handle round off type in sale line and invoice line #5684
There should only be one round down account #5684

Add on change with amount so that amount change shows in tryton client
for round down amount.