[Go] Documentation cleanup of obsolete 'callback' and 'extend' examples.

After commit 17b1c1c (pull request 447; issue 418) the 'callback' and 'extend'
examples have been removed in favor of the 'director' example.

Examples/go/extend/example.h

@@ -1,56 +0,0 @@
-/* File : example.h */
-
-#include <cstdio>
-#include <iostream>
-#include <vector>
-#include <string>
-#include <cmath>
-
-class Employee {
-private:
-	std::string name;
-public:
-	Employee(const char* n): name(n) {}
-	virtual std::string getTitle() { return getPosition() + " " + getName(); }
-	virtual std::string getName() { return name; }
-	virtual std::string getPosition() const { return "Employee"; }
-	virtual ~Employee() { printf("~Employee() @ %p\n", (void *)this); }
-};
-
-
-class Manager: public Employee {
-public:
-	Manager(const char* n): Employee(n) {}
-	virtual std::string getPosition() const { return "Manager"; }
-};
-
-
-class EmployeeList {
-	std::vector<Employee*> list;
-public:
-	EmployeeList() {
-		list.push_back(new Employee("Bob"));
-		list.push_back(new Employee("Jane"));
-		list.push_back(new Manager("Ted"));
-	}
-	void addEmployee(Employee *p) {
-		list.push_back(p);
-		std::cout << "New employee added.   Current employees are:" << std::endl;
-		std::vector<Employee*>::iterator i;
-		for (i=list.begin(); i!=list.end(); i++) {
-			std::cout << "  " << (*i)->getTitle() << std::endl;
-		}
-	}
-	const Employee *get_item(int i) {
-		return list[i];
-	}
-	~EmployeeList() { 
-		std::vector<Employee*>::iterator i;
-		std::cout << "~EmployeeList, deleting " << list.size() << " employees." << std::endl;
-		for (i=list.begin(); i!=list.end(); i++) {
-			delete *i;
-		}
-		std::cout << "~EmployeeList empty." << std::endl;
-	}
-};
-