Add option to round up RT

[Elyahu41]

This might be something you want to leave out. However, in the apps, I by default round up the zman of Rabbeinu Tam because I figured most people would want that. And if people do not want that, I made an option to disable it.

As mentioned in issue #15 , there should be an option/setting to allow the user to choose whether or not they want to round up RT.