Hoardomatic Code: Gem Class

Last class. Gems have their own bundle of properties, so they get their own class. Gem String gem_name: Name of the gem. Double val_constant: The value constant for the stone, the V in the(C^2 + C*4) * V value formula. Double carats: Weight of the gem in carats. This one is similar to the previous two, but it takes on itself the task of randomly selecting a node from Gems.xml to turn into an