5/7 Update: Bug Fixes/Gameplay Improvements

A rather small update but an important one for fixes.

*  Have finally fixed treasure chests, they should work properly now.

*  Added a random stat increase to each level up.

*  Adjusted enemy stats slightly upward to balance the random stat increases.

*  Reduced cost of potion to 10 gold.

*  Changed the floor tiles in the caves, I really like the change.

*  Fixed a bug where you couldn't progress beyond Chapter 1.

*  Added attack as a factor to the physical "to hit" formula, agility is still the main factor.

*  A few other minor changes to the caves appearance.