Improve Time Handling

Time handling in Mifos, especially with respect to unit tests, is cumbersome. (why?)

(Kay) - I think we have implemented some of this in Gazelle A

Use case:

• `Testing time-dependent scenarios <https://groups.google.com/group/mifosdeveloper/browse_thread/thread/cdbebc1b675be87d/afd58cdd361ce90a>`_

Potentially helpful library:

Joda Time (already used in Mifos).