Support author object

[Legion2]

When using the jekyll-seo-tag plugin you can specify an author object in the _config.yml:

author:
  name: Leon Kiefer
  twitter: Legion2Leon

This theme does not render the author information correctly. As it expect the author property to be a string. The theme should check if author is an object and use the name property, else fallback to the current behavior.

The current version of the theme renders the author as json object:
{"name"=>"Leon Kiefer", "twitter"=>"Legion2Leon"}