Fix indentation in mirb.c
mruby-sprintf should precede mruby-print
Merge pull request #1070 from mattn/fix_order

mruby-sprintf should precede mruby-print
Merge pull request #1069 from kano4/pr-fix-indentation-in-mirb_c

Fix indentation in mirb.c
remove unused function 'mrb_strerrno' and 'mrb_bug_errno'.
erase removed prototype declaration.
Merge branch 'remove_strerror' of github.com:crimsonwoods/mruby into remove_strerror