I just pushed CodeRunner version 3.0.1 to github. The changes from 3.0.0 are mostly trivial and it's not worth upgrading unless one of the bugs it fixes was annoying you. The change history entry is:
15 July 2016. Version 3.0.1. Minor bug fixes, including:
- Use of Show Differences button with questions containing significant white space output resulted in premature line truncation and/or invalid html output
- Ace editor was not doing syntax highlighting for nodejs questions
- Several panels in question authoring form had monospace labels in Moodle 3.1
Also, the documentation for custom template grading has been rewritten.
The Show Differences button in the result table is still disabled by default and must be enabled via Site administration > Plugins > Question types > CodeRunner, but with the bug fix in this latest version it looks stable and students find it useful. We've been using it for some time here.