Update r.json

Created a color scheme that is really helpful for markdown users, but also very easy to read. Somewhat based on the solarized theme.
![687474703a2f2f692e696d6775722e636f6d2f6335516d3265492e706e67](https://cloud.githubusercontent.com/assets/216426/4616378/1027ce5a-52f3-11e4-94a5-37753d9129ff.png)