Initial GS code engine implementation

- Replaced the cheat file format with YAML
- Replaced the simulate_boot function with a small bit of C, and a loader in assembly
- The loader is fairly well-documented, and points out which register states are required for CICs
- Also includes a giant patcher function (relocatable assembly) which can patch the exception handler and run the code engine
- The code engine is GS Pro 3.30-compatible, and supports all code types