changes in Paginator and QuickSearch (4.3)

* new methods `enablePaginator`, `enableQuickSearch`
* changed methods `addPaginator`, `addQuickSearch`
* rename `Paginator->ipp()` to `setRowsPerPage()`. Renamed only setter
method, not `Paginator->ipp` attribute itself.

@romaninsh - see todo(s) :)