Version 0.2.00

Milestone Combat complete.

Backend changes:
* Added a few new items for enemies to randomly drop.
* Populated `enemy_loot` table with some random drops.
* Wrote code to generate random loot based on chance and number dropped.
* Modified Attack method in Character class to have monsters drop loot on death (this needs to be moved!).  Fixes #51
* Minor adjustments to GetVisible function in Map class to show the items dropped last on top of existin items.
* Added images for the 3 new items.