Added some tests to the GrowthManager. In doing so, I realized that there were a number of changes that would make testing much easier (mostly adding return values to the methods that were just returning void.) The process of adding tests is also revealing some dependencies the objects have on one another. Currently, all of the manager objects are static. While this is convenient for being able to access them where ever they are needed, it is also detrimental in that sometimes the different managers are directly dependent on one another. I'll need to think about the structure and consider adding some interfaces.