[scripts/pyaudio3dtools] cleanup and fixes
- bugfix for PCM files with ISM input
- bugfix for ISM input files where sample count is not an integer multiple of frames (should address #206 (closed))
- bugfix in binaural rendering with
generate_test_items.py
- try to handle accidental specification of sampling rate in kHz, with a warning
- fix a missing comma in cicp13.txt ls layout file
- code cleanup and some new helper functions for the module
- correctly set executable bit on some python files