Update default config

* Adds upcoming rule-delimeter option. Will keep one linespace space between each ruleset.
* Adds sort-order-fallback option for properties not explicitly defined.
* Adds space-between-declarations option to keep each declaration (property: value;) on new lines.
* Makes SASS features appear with a clear linespace before CSS properties. Only applicable when combing .scss.
* Adds src property, so that combing @font-face ruleset doesn't result in .eot always coming last and breaking fonts in Firefox.
* Adds font-smoothing, backface-visibility and text-rendering properties with vendor prefixes as needed.