Add isTablet boolean resource

	new file:   res/values-sw600dp-land/layouts.xml
	new file:   res/values-sw600dp/layouts.xml
	new file:   res/values/layouts.xml
Lock rotation to portrait on smartphones

this closes #59

	modified:   src/com/better/alarm/presenter/AlarmsListActivity.java
	modified:   src/com/better/alarm/presenter/SetAlarmActivity.java
Merge branch 'lock_rotation' into develop