Escape double quotes of the post title

[yous]

This is how to produce this problem.

1. Run rake new_post with a title that has double quotes:

   $ rake new_post
   Enter a title for your post: Post with "double quotes"
   mkdir -p source/_posts
   Creating new post: source/_posts/2014-07-12-post-with-double-quotes.markdown
   

   either

   $ rake new_post["Post with \"double quotes\""]
   mkdir -p source/_posts
   Creating new post: source/_posts/2014-07-12-post-with-double-quotes.markdown
   

   Then the content of 2014-07-12-post-with-double-quotes.markdown:

   ---
   layout: post
   title: "Post with "double quotes""
   date: 2014-07-12 00:00:00 +0000
   comments: true
   categories: 
   ---

2. Run rake generate:

   $ rake generate
   ## Generating Site with Jekyll
   identical source/stylesheets/screen.css
   Configuration file: /path/to/octopress/_config.yml
               Source: source
          Destination: public
         Generating...
   Error reading file /path/to/octopress/source/_posts/2014-07-12-post-with-double-quotes.markdown: (<unknown>): did not find expected key while parsing a block mapping at line 2 column 1
                       done.
   

[yous]

Can you also consider this?

[parkr]

/cc @imathis