describe call stack overwritten problem of mrb_get_backtrace; close #1661
escape non-ascii characters correctly in String#inspect
Merge branch 'master' into iij
Merge pull request #1662 from h2so5/fix-string-inspect

escape non-ascii characters correctly in String#inspect
fix utf-8 codepage
Merge branch 'master' into iij
Merge pull request #1663 from h2so5/fix-utf8-codepage

fix utf8 codepage
add enable_debug to build_config.rb
add callback invocation from OP_DEBUG
Merge branch 'master' into iij
clone Class/Module rightly
Merge pull request #1664 from h2so5/clone-class-module

clone Class/Module rightly
Merge branch 'master' into iij
Merge branch 'iij' of https://github.com/iij/mruby