Line now uses new style methods - not ready to merge yet

Hi all,

This one was pretty straight forward, no problems. It did highlight for me the value of getting instance variables for styles since I changed a bunch of instance variable calls to method calls which look up style (I'll point that out in-line).

I also removed the `gui_opts` because it doesn't look like we're using those. I'll point that out in-line too.
Since `create_link` creates a real `Shoes::Link`, it gets the full style hash from the dsl. Even if we don't want to hang on to setting all the styles, I think this edit is more robust than the old way.