12 hour format backend change

12 hour format didn't seem to work at all. I would select 12:00 AM, save, and then it would display 6:00 AM once page refreshed. I changed the way 12 hour format is saved in meta data and let PHP do the formatting using strtotime and date instead of using minutes from 00:00.

I made the modifications for something I was working on and thought I'd share the changes so others can use this nifty plugin as well.

Thanks.