Update to WPF 0.1.8

-Updated to latest Zurb Foundation commit (April 6, 2013)
-Added a domain that was missing from some of the __()/language
functions.
-The quotes get a title that equals the post_slug (if you dont fill in
anything then it will equal to 'quote-{$post_id}').
-bugfix: Quotes can be added without a source (before this change, you
would see 2 parentheses with nothing in between).
-Quote post type is moved to a plugin "wpf_quote".
-The plugin (wpf_quote) also contains a widget to show a random quote.
-The plugin (wpf_quote) got it's own language domain. And come's with
Dutch .mo/.po files.
-The WPF plugin(s) will be in the folder "wpf plugins". If you want to
use the(se) plugin(s) you will have to move them to your wordpress
plugin folder.