y310/kodama — pull request #1 by y310 (2012-12-03 05:28:34+00:00)
Title: Graceful stop

In general, when user send termination signal like ``SIGQUIT`` or ``SIGINT``, Kodama stops immediately.
But this is likely to make invalid position log because signal interrupts Kodama's main event loop.

To avoid such situation, I add gracefully stop option - ``set_exit_trap_for``.
Kodama stops after processing current event loop by setting signals to this option.