build 180527. smoother camera rotation, semi-persistent cab camera angle between view swaps, configurable default cab camera view angle, diesel engine power calculation fix, minor refactoring and fixes for content files lookups and loading

Train.h

@@ -592,6 +592,7 @@ public: // reszta może by?publiczna
 
     Math3D::vector3 pMechSittingPosition; // ABu 180404
     Math3D::vector3 MirrorPosition(bool lewe);
+    glm::vec2 pMechViewAngle { 0.0, 0.0 }; // camera pitch and yaw values, preserved while in external view
 
 private:
     double fBlinkTimer;