Update to build with GBDK 4.3.0

[tstirrat]

It took me a while, but I managed to get this building with a modern GBDK-2020 v4.3.0

Changes:

• Cleaned up the Makefile, auto-generates a compile.bat (standard for the GBDK examples)
• Moved your old mod for gbdk-n into a GBDK ISR_VECTOR
• Added cartridge name (fixes #8) and MBC type (fixes #10)
• Fix CGB flag, fixes #5
• Removed a bunch of push bc, pop bc since I believe the calling mechanics of GBDK changed

I converted two ASM entry points back to C. I tried NOT to do this but couldn't get it to work in a stable manner without them:

• asmMain -> gameMain()
• asmUpdateMidiBuffer -> updateMidiBuffer()

I've tested it on a DMG-01