* Add cpu_run pre/post exec hooks, to hook the cpu just before / after it runs target code.
* Refactor hooks to separate them in different files
* Remove most extern variables
* Reduce the amount of extra code in QEMU
* Add clang-format script
* refactor and fix edge-related code generation.
- fix sigsetjmp bug
- fix tcg buffer overflow bug due to wrong icount report.
- closer to original QEMU implementation to improve maintainability.
- use the right TB icount / size semantic
- report problems related errors during generation
