1. Data_IO.f90 routines reads from 'parameter.dat' file simulation data.
2. Grid1D.f90 no longer defines 'dtfact', rather routine in Data_IO.f90
do it.
3. MD_HydroSubroutine.f90 is now able to select 'Reconstruction Scheme'
for fluxes during runtime (Strategy Pattern).
4. Runge_kutta_2nd_BCs.f90 evolve both 'metric' and 'hydrodynamic'
quantity. 
5. main_BSSN_1D.f90 is changed to run for certain time not iteration.
And reads calls Data_IO.f90 subroutine to read simulation
data(reconstruction scheme, dtfact etc.).
1. Data_IO.f90 routines reads from 'parameter.dat' file simulation data.
2. tmp_mdsimdata.f90 contain data structure for storing information
about simulation (dtfact, hydroonly, maxtime etc.)
3. Norm.f90 calculate 'L2 and Infinite norm'.
4. Runge_kutta_2nd_BCs_HydroOnly.f90 only evolves 'hydrodynamics'
quantities. 
5. 'Shock_Tube.f90' contains initialization for 'Shock Tube'.
6. Makefile is change to recognize add source files.
1. parameter.dat contains simulation parameter. Read the parameter.dat
for details.