Remove lint-spaces task.

![evilmaxwell-1389712606](https://cloud.githubusercontent.com/assets/583202/2891406/43e1d612-d532-11e3-8f40-0764ad42713f.png)

Removing `grunt-lint-spaces` task since it was causing errors with JSDoc style comments for functions/mix-ins and `scss-lint` should be handling most indentation linting.