more comments for the Sod 1D fortran porting from the Chang 95 paper
add new method to replace and refactor the old one
more comments and new method check_input
correct x step number for the mesh of the analytic solution
rename itp as grid_numbers_on_mesh
rename grid_numbers_on_mesh as mesh_pt_number_x
add one more method get_cese_solution_fortran_porting_2
rename mesh_pt_number_x as itp
use appropriate iteration number to make the grids are the same
decouple mesh x and iteration. runable but the result is incorrect
decouple mesh x and iteration. result consistent to get_cese_solution_fortran_porting
decouple mesh x and iteration. result consistent to get_cese_solution_fortran_porting. different mesh example
* Merged in tai271828/solvcon (pull request #44)

* 1D Sod gasdyn: refactor the porting fortran to decouple the mesh and iteration number

* More comments and arrange the layout of the code (pep8)