Add Kernel.Hash
Merge pull request #2617 from suzukaze/add-kernel.Hash

Add Kernel#Hash
Add Kernel.Float
Merge pull request #2618 from suzukaze/add-kernel.Float

Add Kernel#Float
Refactor mrbc_context_new func
Merge pull request #2619 from suzukaze/refactor-mrbc_context_new

Refactor mrbc_context_new func
Refactor yylex func
Merge pull request #2620 from suzukaze/refactor-yylex

Refactor yylex func