Added constructors.
Revert "Added constructors."

This reverts commit bca93302e50e94cbfa750d9d9e0027947eeaad24.
Added constructors.

Modified the Checking and Savings classes to allow the passing of
balance and rate through their constructors instead of setting the
values directly as seen in cAct(). Abstract getInterest method was
removed as well because it was only overriding rate which is now chosen
based on the object type.