Updates on MFEM DMD examples

[siuwuncheung]

• Add representation command lines and results in DMD examples. Each file now includes the results on libROM webpage and 1-2 more examples
• Remove command lines copied from MFEM.
• Fix a visit visualization issue in nonlinear elasticity DMD, where the deformed mesh should be used.
• Remove the pauses in glvis visualization. Otherwise users are required to press space in all the glvis windows after initialization to resume the run.