Includes simple example in main gb.rs file.

Includes proper string representation.

Improved build system for the boot ROMs.
Better comments in the ROM code.

Allows usage of pytest for testing python code.

CGB is now going to boot using Boytacean ROM by default.
Allows better image and open source only boot.

Making it possible to indirectly access the registers via constants.

Adds OBP0_ADDR and OBP1_ADDR to the list of registers.