Add header parsing for Genesis, ROM size autodetection, checksum validation.

Reads and does some parsing of internal header in Sega carts.

Example usage and output:

$ ./inlretro --lua_filename=scripts/inlretro2.lua --dump_filename=dump.bin --console=genesis
Successfully found and connected to INL retro-prog
Device firmware version: 2.3.x 
Console Name:   SEGA MEGA DRIVE 
Domestic Name:  BONANZA BROS.                                   
Release Date:   (C)SEGA 1991.JUL
Rom Size:       512.0 kB (4.0 mbit)
Serial/Version: GM MK-1124 -00
Checksum:       0x5D81
ROM Size not provided, 512.0 kB (4.0 mbit) detected.

Dumping SEGA ROM...
dumping ROM bank:       0        of     3.0
DONE Dumping SEGA ROM
Computing checksum...
CHECKSUM OK! DUMP SUCCESS!