updated rpgmaker mz core to 1.2.0

• Updated project to RPGMaker MZ v1.2.0
• Corrected height of lamp post on the port map, one was higher than the other previously.
• Corrected / Updated Credits page.

Will be implementing other things on the map by the end of the month, when i can find time.

Edit: Just found out that BGM doesn't loop anymore when game is run on Firefox (even though FPS have improved slightly - in the 15-17 range - suckage is still better than nothing).

With this edit, i will stop working on this project. Too much trouble to be worth the bother.