Hotfix: yield is a keyword in PHP5.5, replaced with `yield_content`

[notacouch]

yield is a keyword as of PHP 5.5, ergo I replaced the yield() function with yield_content(). Seems to have done the trick.

Also removed <base href="" />:

• Don't see the reason for it.
• Working locally on shared development, each person might create their own unique local domain.
• Until I change the base_url the site will hang while searching for assets on its default (too much of an assumption for a boilerplate?)