Headers refined

src/demo_GMR01.cpp

src/demo_GPR01.cpp

src/demo_HSMM_batchLQR01.cpp

src/demo_LWR_batch01.cpp

src/demo_LWR_iterative01.cpp

src/demo_MPC_batch01.cpp

src/demo_MPC_iterative01.cpp

src/demo_MPC_semitied01.cpp

src/demo_MPC_velocity01.cpp

src/demo_Riemannian_S2_GMM01.cpp

src/demo_Riemannian_S2_TPGMM01.cpp

src/demo_Riemannian_S2_infHorLQR01.cpp

src/demo_Riemannian_S2_product01.cpp

src/demo_Riemannian_S3_TPGMM01.cpp

src/demo_Riemannian_S3_infHorLQR01.cpp

src/demo_Riemannian_SPD_GMR01.cpp

src/demo_Riemannian_SPD_GMR_Mandel01.cpp

src/demo_Riemannian_SPD_interp02.cpp

src/demo_Riemannian_pose_GMM01.cpp

src/demo_Riemannian_pose_TPGMM01.cpp