Stringify ids.

Fixes #39.
Fix href for comments 4,5,6 in JSON read example
Remove invalid href in example

This href looks to be from a previous example where we were looking at
photos. We don't need the href attribute in this example because we have
a url template.
Change 'posts' to 'photos' to match response attrs
Merge pull request #55 from chrishunt/chrishunt/fix-comment-hrefs

Fix href for comments 4,5,6 in JSON read example
Merge pull request #56 from chrishunt/chrishunt/remove-href-for-post-document

Remove invalid href in write example
Merge pull request #57 from chrishunt/chrishunt/change-posts-to-photos

Change 'posts' to 'photos' to match response attrs
Merge pull request #54 from oriolgual/master

Stringify ids.