fixed typo and meta tags

fixed typo, it should be titleized not tileize
meta tags should close with "/>"
changed condition for yield

<% if content_for?(:seo_meta) %> is not required for yield(:seo_meta)
also updated the readme.md with the change
changed create_a_blog_post default options

changed create_a_blog_post default options so we don't need to call them
explicitly every time we want to create a blog