gbr 
Yet another Game Boy emulator in Rust.

Prerequisites
Status
- [x] CPU
- [x] Instructions
- [x] Instruction timing
- [x] Interrupt handling
- [ ] PPU
- [x] Background
- [x] Window
- [x] Sprite
- [x] V-blank interrupt
- [x] LCDC STAT interrupt
- [x] Sprite and background priority
- [ ] OAM bug
- [x] Joypad
- [x] Joypad input
- [x] Joypad interrupt
- [ ] Catridge
- [x] Catridge loading
- [x] Data
- [x] MBC1
- [ ] MBC3
- [ ] MBC5
- [ ] External RAM persistence
- [x] Timer
- [x] Timer registers
- [x] Timer overflow interrupt
- [ ] APU