Changed default boost/brightness range in config.h

When controlling brightness by adjusting the boost duty cycle, the
duty cycle may now be adjusted between 8% and 51% through the
configuration menus.  For reference, the Adafruit firmware allows the
duty cycle to be adjusted from 12% to 40% through the menus.
Extended display pulsing options

The display pulsing may now be enabled during the alarm only or during
snooze in addition to both or neither.  Additionally, the alarm
indicator ("-") only blinks during alarm or snooze if the display is
not pulsing.
Automatic drift correction improvement (minor)

The automatic drift correction algorithm now works better when time
adjustments span a daylight saving time change.
Automatic off and alarm improvement

If the display is inactive due to the automatic-off feature, the
display is temporarily activated when the alarm first sounds.  After
this commit, the display will be temporarily activated when the alarm
sounds after a snooze period.
Merge branch 'master' into russell