Extend the level index past $10 in Sonic 2

Authoring Notes

(Original guide by kram, current revision that fixes major bugs and extends properly by GARY 'M 9) (Updated again by kram, adding back custom titlecard mappings howto, due to guide being unfinished, thus finally fixing the "ZONE ZONE" bug. Replace all the empty levels with your new ones.) (Some implementations by silent.creature. More fixes about level crashes)

Introduction

WARNING: Unless you are working with Xenowhirl's 2007 Sonic 2 disassembly, I [b]strongly[/b] recommend you port the Sonic 1 sound driver first before proceeding. There will be a lot of shifting data and data addition here, and this may even break any array built under Sonic 2 or Sonic 2 Beta sound driver. In Xenowhirl's disassembly, the Sound Driver is assembled within the ROM, so it can handle a massive data shift. This time, I will leave for the reader the option to add data as long as necessary, instead of labeling and inserting all data (maybe not everyone has all the data done, right?)

You probably noticed that all the indexes in the game stop at $10 and when you try to extend it, by extending the MLLB (Main Level Load Blocks), you get weird glitches or even crashes, that is because you haven't extended all the indexes that need to be extended.