rename obsolete mrb_special_const_p to mrb_immediate_p
turn string obsolete functions into macros
Merge branch 'master' of github.com:mruby/mruby
Merge branch 'master' of github.com:mruby/mruby
Add write_barrier docs
Merge branch 'add-gc-docs' of https://github.com/suzukaze/mruby into suzukaze-add-gc-docs
write barrier doc update
git push origin masterMerge branch 'suzukaze-add-gc-docs'