Handle HTTP request body params better.

See [PEAR Bug 17806](https://pear.php.net/bugs/bug.php?id=17806)

[RFC 5849 section
3.4.1.3.1](http://tools.ietf.org/html/rfc5849#section-3.4.1.3.1) says
any request can have params in the request body provided the
content-type is set correctly and the entity-body is single-part and
formatted correctly.
Merge pull request #5 from gauthierm/bug-17806-delete-method

Handle HTTP request body params better.