sleep buttons correctly
Merge pull request #3 from tpwrules/master

Sleep buttons correctly (thanks Thomas!)
Added tpw_rules to CREDITS
Minor alarm code revision

The alarm_tick() function has been revised for clarity.  Also, the
display now remains active whenever the the alarm is sounding or the
clock is snoozing--regardless of the auto off settings.
Merge branch 'master' into russell

Conflicts:
	firmware/alarm.c