Add support for old sass syntax (sass-convert --old)

* Add support for old sass syntax (sass-convert --old)
* Upgrade sass version to latest

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![screen shot 2013-10-28 at 12 12 58 pm](https://f.cloud.github.com/assets/26019/1417521/a74e2cc0-3f8f-11e3-9869-ebe749dadb44.png)