Timer now contains an invoker instead of inheriting

the idea is that an invoker holds a weak_ptr to a steppable. and
anything with an invoker can advance a steppable

app::add_sort has become too heavy because of the way timer and
invoker are initialized now.

src/timer.cpp

@@ -1,21 +1,24 @@
 #include <chrono>
 #include <iostream>
+#include <memory>
 
 #include "timer.hpp"
+#include "Invoker.hpp"
 
 using namespace std::chrono;
 using namespace std;
 
-Timer::Timer(size_t triggeramount, milliseconds triggerinterval)
+Timer::Timer(size_t triggeramount, std::unique_ptr<Invoker> invoker, milliseconds triggerinterval)
 	:triggeramount(triggeramount)
-	, triggerinterval(triggerinterval) {}
+	 , invoker(std::move(invoker))
+	 , triggerinterval(triggerinterval){}
 
 void Timer::add_time(milliseconds deltatime) {
 	accumulator += deltatime;
 	if (accumulator >= triggerinterval) {
 		accumulator -= triggerinterval;
 		cout << "request in timer\n";
-		request();
+		invoker->request();
 		triggercount++;
 		if (triggeramount != 0 && triggercount >= triggeramount){
 			isexpired=true;
@@ -24,7 +27,7 @@ void Timer::add_time(milliseconds deltatime) {
 }
 
 void TimerManager::add_timer(Timer timer){
-	timers.push_back(timer);
+	timers.push_back(std::move(timer));
 }
 
 void TimerManager::update_timers() {