Reduce a snprintf() call in localjump_error().
Replace tabs with spaces
Move src/sprintf to mrbgems/mruby-sprintf/src/
Merge pull request #942 from kano4/master

Replace tabs with spaces
Separate Kernel#sprintf support from mruby core. It's moved to mrbgems.
Merge pull request #943 from monaka/pr-tmp-move-sprintf-to-mrbgem

Move Kernel#sprintf to mrbgem
save/restore arena index for each codedump iteration
proper irep pool duplication check for strings
Added a link to the contribution guidelines in the README
Merge pull request #945 from carsonmcdonald/refguidelines

Added a link to the contribution guidelines in the README
Include stdio.h in mrbconf.h instead of C extension sources.
Modify API configuration.
  C API mrb_p() is always callable.
  - But it will do nothing when ENABLE_STDIO is not defined.

  Kernel#__printstr__ is always callable.
  - But it will do nothing when ENABLE_STDIO is not defined.
Merge pull request #937 from monaka/pr-remove-snprintf-from-localjump_error

Reduce a snprintf() call in localjump_error().
Make some printf enclose in #ifdef ENABLE_STDIO.
use mrb_str_buf_new to create a buffer to be used by mrb_str_buf_cat
Add accessor: version, description, summary, homepage.
Merge pull request #946 from monaka/pr-add-more-accessor-to-mrbgem_spec

Add accessor: version, description, summary, homepage.
Merge pull request #947 from monaka/pr-cleanup-stdio-calls-20130304

Cleanup stdio related.
Skip end of loop in mrb_sym2name_len
Remove RB_GC_GUARD(x) macro. See also mruby/mruby#948.