Fix issue #234 Off-by-one in month report title

When I click the month of December 2012, the title of my report view is
January 2013. When I click the final month (currently January 2013), the
title is correct. The result is that the final two months in report view
have the same title.
Merge pull request #235 from roostr/master

Fixed #234 Clicking month bar shows report that's off by one month