Optimize, try to get to at least estimated 200 MHz

[bradgrantham]

• Port optimizations from Rosa, but 80-column didn’t work last time you tried it in desktop emulator
  • Need to also mark regions by softswitch and only update those regions when that softswitch changes.
  • Maybe just have RAM and ROM in an array and have the regions_by_page just be a pointer or an offset (use regions to help initialize ROM areas from the ROM blob)
• Attempt to have everything templatized so it can be mostly inlined
  • Make mainboard in main() a static and not a pointer or put in bus
  • Templatize on display and audio functions and board array

[bradgrantham]

Current speed measured on my 2018 MBP Pro 13 is around emulated 12MHz.