Adds :target to list of supported pseudo classes

Adds :target to the pseudos variable in the coffee scripts and
compiles the changes to the kss.js file.

Adding :target allows us to show these modifiers in the generated
style guides. Without support, targetted styles cannot be displayed
without user interaction.
Merge pull request #52 from janiv/targetPseudoClass

Adds :target to list of supported pseudo classes