Fix C++ recording tool clean up (#48)

Author: kaatrasa

cpp/k4a/record.cpp

@@ -249,5 +249,8 @@ int main(int argc, char *argv[]) {
         inputThread.join();
     }
 
+    // Close VIO
+    session = nullptr;
+
     return EXIT_SUCCESS;
 }

cpp/orbbec/record.cpp

@@ -248,5 +248,8 @@ int main(int argc, char *argv[]) {
         inputThread.join();
     }
 
+    // Close VIO
+    session = nullptr;
+
     return EXIT_SUCCESS;
 }

cpp/realsense/record.cpp

@@ -202,5 +202,8 @@ int main(int argc, char** argv) {
         inputThread.join();
     }
 
+    // Close VIO
+    session = nullptr;
+
     return 0;
 }