StatisticsView should always display entitlements

When looking at the StatisticsView, it only displays rows if there are actual absences. However, this misses some important information.

Consider the case in which someone has an entitlement of 10 vacation days in 2014 but has no actual absences. (This could happen because 2014 has just begun and the employee hasn't had a chance to take a vacation yet... or it could be that they never take a vacation at all in 2014.) It's still useful to display a row "2014, Vacation" because the entitlement is important.