provide Command line parameters to rp_extract_batch.py and rp_extract.py

[audiofeature]

rp_extract_files.py should be able to parse command line paramters such as in_filepath, out_filepath and feature types to be able to be called directly from command line instead of edititing the code

use
https://docs.python.org/2/howto/argparse.html

[slychief]

Maybe we should also consider to provide self-contained packages that do not require a Python installation.

Can be done via py2exe and comparable tools. Unfortunately the packages may become really big – from 70 to 250MB.

[audiofeature]

already implemented in_filepath, out_filepath in rp_extract_batch.py, just needs to be copied over to rp_extract.py for a single file