Fix missing calendar row for months that start on Saturday (31 days) or Sunday (30 days)

Currently, when a month has 31 days and starts on a Saturday or when it has 30 days and starts on a Sunday (and that month is *not* December) then the calendar will be missing a table row (e.g. the issue occurs for January '12, April '12, July '12, September '13, etc.).

@grahamscott - Please review.