Missing Mappers

[andymikulski]

WebNES has 24 mappers, we should meet parity in that regard.

This issue is for tracking the conversion of WebNES mappers to nES6 mappers. Pretty simple, albeit a little time consuming. Optimizations can be made within mappers as well to improve game performance (caching, eliminating loops, etc), though generally those can only be tested if you have ROMs that use those mappers.

• [x] ~Mapper 0~
• [x] ~Mapper 1~
• [x] ~Mapper 2~
• [ ] Mapper 3
• [x] ~Mapper 4~
• [x] ~Mapper 5~
• [ ] Mapper 6
• [ ] Mapper 7
• [ ] Mapper 8
• [x] ~Mapper 9~
• [ ] Mapper 11
• [ ] Mapper 13
• [ ] Mapper 15
• [ ] Mapper 17
• [ ] Mapper 34
• [ ] Mapper 41
• [ ] Mapper 64
• [ ] Mapper 65
• [ ] Mapper 66
• [ ] Mapper 71
• [ ] Mapper 78
• [ ] Mapper 79
• [ ] Mapper 180
• [ ] Mapper 206