perf(cell): start refactor value getters
perf(cell): start refactor value getters

swimlane/angular2-data-table,achimha/ngx-datatable,achimha/ngx-datatable,swimlane/angular2-data-table,achimha/ngx-datatable,swimlane/angular2-data-table,swimlane/ngx-datatable,swimlane/ngx-datatable,swimlane/ngx-datatable