Commit before branching.
Moved ppu into nested subproject.
Added the IPPU interface.
Added Builder pattern in console.d.
Removed dependency on PPU in cpu.d
Managed to run some CPU instructions...
Fixed the BIT cpu instruction not setting the overflow bit flag.
Fixed RTS instruction reading stack at address 0x1000 instead of 0x0100.
Fixed PLA instr accessing stack at 0x1000 instead of 0x0100 and not setting flags.