Memory / MMU

[m0xsec]

Implement GameBoy memory management. While the Gameboy didn't actually have an MMU (Memory Management Unit) it makes sense to emulate one.

• [x] ROM
• [x] RAM
• [x] VRAM
• [x] OAM
• [x] I/O Registers
• [x] HRAM
• [x] Handle memory read/write operations for these memory regions

[m0xsec]

Moved bank switching to its own issue #6