updates configure scripts to match also SPECFEM3D_Cartesian ones
updates smoothing, interpolation; makes difference_sem to work in parallel
adds tool addition_sem to src/tomography
fixes filename argument for routine write_kernel_netcdf()
"Buildbot ran code beautifier."
suppressed the "configure" and "make" steps from all the run_this_example.sh
added run_this_example.sh for EXAMPLES/small_benchmark_run_to_test_very_simple_Earth and EXAMPLES/small_benchmark_run_to_test_more_complex_Earth
put the "make clean ; make all" step back in all the run_this_example.sh scripts because in the case of SPECFEM3D_GLOBE the solver is compiled with static array and loop sizes that depend on the mesh under study
updated some comments in four scripts