Skip end of loop in mrb_sym2name_len
Remove RB_GC_GUARD(x) macro. See also mruby/mruby#948.
skip empty OP_STRCAT
Merge pull request #950 from monaka/pr-remove-macro-RB_GC_GUARD

Remove RB_GC_GUARD(x) macro.
Merge pull request #949 from mattn/find_symbol

Skip end of loop in mrb_sym2name_len
Replace tabs with spaces
Add include guard in node.h
Merge pull request #952 from kano4/master

Add include guard in node.h and Replace tabs with spaces