split the huge class

--HG--
rename : sandbox/gasdyn/tube/sodtube1d.py => sandbox/gasdyn/tube/sodtube1d_cese.py
reorg as package
reorg module naming

--HG--
rename : sandbox/gasdyn/tube/sodtube1d/sodtube1d_data.py => sandbox/gasdyn/tube/sodtube1d/handler_data.py
rename : sandbox/gasdyn/tube/sodtube1d/sodtube1d_plot.py => sandbox/gasdyn/tube/sodtube1d/handler_plot.py
rename : sandbox/gasdyn/tube/sodtube1d/sodtube1d_analytic.py => sandbox/gasdyn/tube/sodtube1d/solver_analytic.py
rename : sandbox/gasdyn/tube/sodtube1d/sodtube1d_cese.py => sandbox/gasdyn/tube/sodtube1d/solver_cese.py
rename : sandbox/gasdyn/tube/sodtube1d/sodtube1d_porting.py => sandbox/gasdyn/tube/sodtube1d/solver_porting.py
abstract mesh generator
get a runnable run.py and tested. looks ok
rm useless code and modulize the iteration of the status before half dt
encapsulate the mesh generator
enculpslate more iteration methods
init sodtube1d.ipynb, use inline image to show mesh
keep the solution values and remove the fortran porting code
stop to use delta_precision as a global var, more comments
implement is_a_solution
implement is_identical_solution. this is convenient when refactoring
refactoring the naming mtx to be mtx_
refactoring the naming mtx to be mtx_
refactoring solver_cese.py: abandon notation dt
refactoring solver_cese.py: abandon variable hdt
refactoring solver_cese.py: abandon variable hdx and dx
refactoring solver_cese.py: abandon variable qdx
refactoring solver_cese.py: abandon variable dtx