Switched to attr_reader to better enforce data object encapsulation.

Merged:

commit 1e5e10f3c26d76179c6012d8017fc516905c77ea
Author: Abraham Heward <aheward@rsmart.com>
Date:   Tue Mar 11 07:45:08 2014 -0700

    A working Observer pattern. Needs to be more fully implemented in the appropriate places, but what's there now will work in the areas we need it to right now.