[escher] Add methods viewWillAppear/Disappear in view controller instead

of keeping track of dataHasChanged in the selectable table view

Change-Id: Id2626f527f44714e29b9bd66e2c843193e1b57b5

apps/graph/values/function_parameter_controller.cpp

@@ -35,7 +35,7 @@ void FunctionParameterController::setFunction(Function * function) {
 }
 
 void FunctionParameterController::didBecomeFirstResponder() {
-  m_selectableTableView.dataHasChanged(true);
+  m_selectableTableView.reloadData();
   m_selectableTableView.selectCellAtLocation(0, 0);
   app()->setFirstResponder(&m_selectableTableView);
 }