Add links to switch between sorted/unsorted colors.

Placed the links next to "Unique Colors" heading - found no other
really suitable place.

Appending ?sorted=true to URL will render the sorted version.
Default is not sorted aka source order.

Injected three additional variables to the model:

- sorted : true when rendering in sorted mode.
- unsortedUrl : URL linking the unsorted version.
- sortedUrl : URL linking the sorted version.

Re-compiled CSS.
Sort font sizes only when sorted=true option set.

So that the sorted/source_order option affects this as well.

Dropped fontSizeSorted field and using fontSize - like done
with other properties.
Avoid errors when sorting missing properties.

Instead of returning false from parseDeclarations when no properties
found, return an empty array, which can safely be sorted and manipulated
afterwards without a need of special casing it.