Make main scripts consistent and add textx debug option

There are several scripts in scripts: The unnecessary scripts should be removed (who needs get_grammar_string.py?), the partially redundant scripts should be unified. For example run_locally.py, run_model.py, run_remotely.py can be one script with appropriate command line args.

In addition, the textx debug option (True or False) should be made available by a switch so that we do not have to edit the scripts to turn on and off the textx debug output.