[bug] linkItField.linkAttributes exists in the documentation, but not in the code

[tomdavies]

The readme file refers to it being possible to access a linkAttributes property:

 {{ entry.linkItField.linkAttributes }}

but that doesn't actually work:

Twig Runtime Error – [Twig\Error\RuntimeError](http://twig.sensiolabs.org/api/2.x/Twig/Error/RuntimeError.html)
Calling unknown method: presseddigital\linkit\models\Entry::linkAttributes()

Being able to access all the generated link attributes (inc href) would be super useful for when you need to build the inner HTML of a link manually, but still want to access attrs like target etc etc. Verb Navigation does this well.

Feels like this would be pretty easy to add - happy to PR if it's likely to be accepted

[ben-callaway]

Thanks for raising @tomdavies. We'll look to add some additional helper methods, getAttributes() and getAttribute(‘name’).