mruby/mruby — pull request #550 by tsahara-iij (2012-11-13 07:59:17+00:00)
Title: fix the issue String#slice with Range may return broken String.

If String#slice has an end-excluded Range object, it may return a broken String.

```
% bin/mruby -e 'p "abc"[1..3]'
"bc\000"
```
(confirmed on OpenBSD/amd64, NetBSD/amd64, CentOS6/x86_64 and MacOSX)