mruby/mruby — pull request #1489 by murasesyuka (2013-08-25 04:33:42+00:00)
Title: showing line number into prompt of mirb

before

```shell
>
* def foo
* :foo
* end
=> :foo
>
* foo
=> :foo
>
```

after

```shell
:001 >
:002 * def foo
:003 * :foo
:004 * end
=> :foo
:005 >
:006 * foo
=> :foo
:007 >
```