Bug Fix for Calendar Month Grid with touch points.

Hi Devin,

Thank you for the wonderful library. 
However, it might be worrisome when using. 
Since it seems to be a bug, a pullrequest is sent. 

On the day of some conditions(e.g. 2012/07/29 row is over 4),
 a UIViewController allocated and pushViewController it
 in TKCalendarMonthView.didSelectDate App will be crash in .

Although it seems to be OS instead of a library, 
a fundamental cause is happy if you profit.