Target and support Android 4.4 (API 19). Closes #101

KitKat changed the behavior of the alarms, so force KitKat to
use exact alarms.

Signed-off-by: Greg Meiste <greg.meiste@gmail.com>
Clear notification if activity opened differently. Closes #93

Previously, Question and Race notifications were only cleared if
clicked on. However, user could open activity without using the
notification by touching the icon or widget. In addition, the
notifications weren't cleared when user opens app using the
Active Display feature on Moto X. This patch covers these
additional use cases.

Signed-off-by: Greg Meiste <greg.meiste@gmail.com>