[#89] remove resize event handle

include/vkcv/Window.hpp

@@ -21,6 +21,7 @@ namespace vkcv {
 		GLFWwindow *m_window;
 		SwapchainHandle m_swapchainHandle;
 		bool m_shouldClose;
+		event_handle<int, int> m_resizeHandle;
 
     public:
     	/**

src/vkcv/Window.cpp

@@ -136,7 +136,7 @@ namespace vkcv {
         Window::e_key.unlock();
         Window::e_char.unlock();
         Window::e_gamepad.unlock();
-        
+		Window::e_resize.remove(m_resizeHandle);
         if (m_window) {
         	s_Windows.erase(std::find(s_Windows.begin(), s_Windows.end(), m_window));
         	glfwDestroyWindow(m_window);

src/vkcv/WindowManager.cpp

@@ -26,9 +26,10 @@ namespace vkcv {
 		SwapchainHandle swapchainHandle = swapchainManager.createSwapchain(*window);
 
 		if (resizeable) {
-			window->e_resize.add([&](int width, int height) {
+			const event_handle<int, int> &resizeHandle = window->e_resize.add([&](int width, int height) {
 				swapchainManager.signalRecreation(swapchainHandle);
 			});
+			window->m_resizeHandle = resizeHandle;
 		}
 
 		m_windows.push_back(window);