Item Price info panel. Customers sorting.

Added ability to sort Customer column by Parent Customer and then by Customer on the Price Info panel -> Other Customers History

After clicking on the Customer label on the header of the column:

Customers should be sorted with the Parent item

for example:

we have

• Parent: Microsoft   Child: Microsoft – ukr
• Parent: Nestle         Child: Nestle – ukr
• Parent: Microsoft   Child: Microsoft – rus
• Parent: Nestle         Child: Nestle – rus

after the sorting should be:

• Parent: Microsoft     Child: Microsoft – ukr
• Parent: Microsoft     Child: Microsoft – rus
• Parent: Nestle           Child: Nestle – ukr
• Parent: Nestle           Child: Nestle – rus