replaced all prints and logging calls with a central configurable logger. I...

replaced all prints and logging calls with a central configurable logger. I did not do it in dev_tools/. The current configuration also creates log_files. I found that quite useful but I do not know whether it should be done by default... also usually you only know that you need the log files AFTER problems happened. I had to do a little clean up in priority_dispatching_framework.py.