Perform a glFinish at the beginning and the end of the performance measurement frame to capture all OpenGL timings

src/performance/performancemeasurement.cpp

@@ -46,6 +46,7 @@ PerformanceMeasurement::PerformanceMeasurement(std::string identifier,
 }
 
 PerformanceMeasurement::~PerformanceMeasurement() {
+    glFinish();
     auto endTime = std::chrono::high_resolution_clock::now();
     auto duration = std::chrono::duration_cast<std::chrono::microseconds>(
         endTime - _startTime).count();