Add track by on rows in order to get rid of console error shown when…

[gabistiufliuc]

… there are duplicates in ng-repeater

[andyperlitch]

The reason this is failing is because during the compile function of the apMesaRows directive, the ng-repeat-start attribute value is being updated with the appropriate track by clause. I am unsure why row.$$$index is undefined since it should always be set (here in updateVisibleRows and here in updateVisibleRowsAsync). The reasons why it does not get set on some rows is the real source of this bug.