Stop showing normal output by console unless debugging.
From Debian bug 688523 (http://bugs.debian.org/688523):
When I start bokken from the GNOME menu, bokken dumps a whole bunch of
debugging output (including pyew/radare dumps) to stdout, which ends up
in ~/.xsession-errors and will never be seen by most users. I would
suggest that this output be disabled unless a debug mode is enabled or