jqxGrid: when sortmode many is active, savestate saves only the last sorting

[Svetoslavb04]

Describe the bug When sort mode many is active, savestate saves only the last sorting

To Reproduce Steps to reproduce the behavior:

1. Go to https://jsfiddle.net/mogador/th5j3dLv/
2. Sort grid with columns [In Stock] and [Quantity]
3. Click on savestate
4. Clear the sortings on columns [In Stock] and [Quantity]
5. Sort grid on column [product]
6. click on [Load State]
7. See that only quantity is loaded as sorting and the product sorting stays