v0.0.1: Implement initial functionality

This version adds a button named "SMS ROM" at the top right corner on the screen.
When this button is clicked a Sega Master System ROM is generated; this ROM can be executed on an appropriate emulator, or even on real hardware if you have a flashcart.

What already works:

• The background tiles;
• The player shows and can walk around the current screen.

What still doesn't work:

• The player can't walk between screens;
• The NPC's, Enemies and Objects still aren't working at all
• The ROM still uses SMS-Puzzle-Maker's interface.