Additional functionality:
 - one may now monitor (`watch`) the `hw_params` file for a non-UAC
   digital audio interface
Improvements:
 - `fetch_alsadevices_list`: put the display (`summarize`) and prompt
   (`prompt_watch`) functionality in their own functions
 - `alsa_device_busy`: improved the handling of failed `lsof` attempts
   when a program
   (other than pulseaudio) has the alsa hw device in use: now it
   informs the user and advices to run the script as root
 - improved the display and naming of the results (see global vars and
   `summarize`)
Cleanup:
 - adhere to the bash styleguide (function prefix for functions)