Support MultiSelect

[marcosmichel89]

I recently did a test with tableview and I have not found the multiselect option, there is a contribution from a user who has uploaded the code that allows multiselect, and it really works for an environment where paging does not exist, but I need to use pagination and also the multi-selection of elements in the table of contents. The pull request is this

enable this features:
mTableView.setSelectable(true);
mTableView.getSelectionHandler().setShadowEnabled(true);
mTableView.getSelectionHandler().setMultiSelectionEnabled(true);

It is expected to be able to select more than one row or deselect one of the marked rows, and also to be able to maintain the state of the paging if desired or not, but an error is received.

E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.tableviewexample, PID: 24372
java.lang.NullPointerException: Attempt to invoke interface method 'void com.tableviewexample.evrencoskun.handler.ISelectableModel.setSelectionState(com.tableviewexample.evrencoskun.adapter.recyclerview.holder.AbstractViewHolder$SelectionState)' on a null object reference
at com.tableviewexample.evrencoskun.handler.SelectionHandler.setSelectionStateRowHeader(SelectionHandler.java:213)
at com.tableviewexample.evrencoskun.handler.SelectionHandler.clearAllSelection(SelectionHandler.java:500)
at com.tableviewexample.evrencoskun.handler.SelectionHandler.setSelectedRowPosition(SelectionHandler.java:392)
at com.tableviewexample.evrencoskun.listener.itemclick.RowHeaderRecyclerViewItemClickListener.clickAction(RowHeaderRecyclerViewItemClickListener.java:55)
at com.tableviewexample.evrencoskun.listener.itemclick.AbstractItemClickListener$1.onSingleTapConfirmed(AbstractItemClickListener.java:65)

• TableView version: [0.8.9.2]
• Android version: [28]