Updated GraphDataCalculator to calculate upper and lower bounds of a
given array (in this case all we have to use is net worth, so it
calculates the upper and lower bounds of net worth)

Updated ScenarioDetailGraphFragment to graph the upper and lower bounds
of net worth.

Renamed 'DummyContent' to 'MenuButtons'...still not sure if we need this
class at all, right now all it seems to be for is as a way to get the ID
of menu buttons of the list fragment.