Failed to build posts.
So I did `cabin new newblog` and ran grunt. 
It failed with this:
`Running "pages:posts" (pages) task
Fatal error: Cannot call method 'toString' of undefined`

It builds ok if there is no code tags like `javascript` in the `.md` files. 
I downloaded just grunt-page on its own to build the same file, failed again.
Maybe I am doing something wrong here. Can anyone have a look at this please?

Thanks .
