Implement ZK Spreadsheet Event Listeners

ZK Spreadsheet supports numerous events such as mouse events, key events, selection events, editing events and data events. You can listen to these events to develop highly interactive spreadsheet applications. For example by listening to editing events such as onStartEditing and onStopEditing you can control which cell user can edit, what is being entered/edited and possibly apply some styling or value transformation once the editing is stopped. Similarly you can listen to certain mouse events such as onCellClick, onCellRightClick, onHeaderClick, onHeaderRightClick etc and update other ZK components or pop up a menu.