Don't clobber `in` and `name` fields in body/form parameters

Fixes #2.  I'll try to follow this up with a corresponding test script.
I don't get how this works... So the "pet" name is not in the body, so therefor it use the $ref directly on the json body...?

Even though I really like the idea on checking the body directly, I'm not sure if this is according to the spec. Could you refer to the specification?