Feature: Framerate display window (#6822)

Frame rate and various game loop/graphics timing measurements and graphs. Accessible via the Help menu, and can print some stats in the console via the fps command.

src/aircraft_cmd.cpp

@@ -37,6 +37,7 @@
 #include "core/backup_type.hpp"
 #include "zoom_func.h"
 #include "disaster_vehicle.h"
+#include "framerate_type.h"
 
 #include "table/strings.h"
 
@@ -2038,6 +2039,8 @@ bool Aircraft::Tick()
 {
 	if (!this->IsNormalAircraft()) return true;
 
+	PerformanceAccumulator framerate(PFE_GL_AIRCRAFT);
+
 	this->tick_counter++;
 
 	if (!(this->vehstatus & VS_STOPPED)) this->running_ticks++;