create expanded adder demo for simple integration of memory controller

Currently there is an adder loop which simply adds 5 to the value in a particular memory location and then stores it in another. This was done as a simple demonstration of using the memory controller.

This could be expanded into more a comprehensive demonstration by having the memory controller read a value from two locations in memory, add them together and place them in a new value.

This could could be done in a progressive fashion to allow a cyclic computation to occur and possibly help produce a speed test.