Fix crash when deleting all electrodes on spike sorter

Source/Processors/SpikeSorter.cpp

@@ -517,7 +517,8 @@ bool SpikeSorter::removeElectrode(int index)
 void SpikeSorter::setElectrodeName(int index, String newName)
 {
 	mut.enter();
-    electrodes[index-1]->name = newName;
+	if ((electrodes.size() > 0) && (index > 0))
+		electrodes[index-1]->name = newName;
 	//updateSinks(electrodes[index-1]->electrodeID, newName);
 	mut.exit();
 }