Add loadself
original commit by miura1729
https://github.com/miura1729/mruby/commit/534e1915199682169e5db2b213f839c02004ec8b
Comment fix for x86 compare instruction
original commit by miura1729
https://github.com/miura1729/mruby/commit/7e4bda639a3a1aed9fb2315453127e82479e9981
Refactor program
original commit by miura1729
https://github.com/miura1729/mruby/commit/6f650e197de4f1f9cc9cfeb40d9fa14acf885f8a
Support Float in addi and Add subi
original commit by miura1729
https://github.com/miura1729/mruby/commit/6495cd02813d59268c3f5f79938142100c10c6d5
use label