Tune up extend parse_wQR.py

[yarikoptic]

https://github.com/ReproNim/reprostim/blob/master/Parsing/parse_wQR.py

• enable basic python logging which would log to stderr not to stdout. kinda done -- prints to stderr., ok for now
• for every detected qrcode displayed, gather a record which would consist of time when it started to appear relative within video from the beginning and when it finished to appear, and complete decoded QR code record
  • figure out actual time in seconds since video start
• print record to stdout using json.dumps() serialization (without any indenting, just 1 line) as soon as gathered
• at the end log how many records where detected and may be how long it took to go through the file