added testdata to repository.
updated read_multiline_command()
implemented long-format for GRID. read_multiline_command() now accepts None for “chunk_char” parameter.
renamed read_multiline_command() to read_multiline_chunk()
implemented use of read_command_args() in all command parsers.
updated main() of nas.py
resolves #1, the component would be invalid with the “-3” in it.