Define function under module except Kernel
Treat a warning as an error
Add call2 which uses cfunc_with_env to hold c function
Use bind2 as default
Use cfunc_with_env for instance method binder
Remove unneeded binder method
Remove unneeded functions
Define instance method under class
Define constructor function using cfunc_with_env
Factor out defining constructor and instance method
Bind static method using cfunc_with_env
Factor out GetClass method
Rename argument check macros
Remove binder.rb
Make able to define function under module
Merge branch 'cfunc-with-env'
Remove warning supressing code
Remove warning supressing code
Use new mruby API (cptr, instead of voidp)
Confirm arena is not increased #5