Support for `chameleon-request-hash` on request/responses

• Added the chameleon-request-hash header on requests to signal which hash should be used
• Added the chameleon-request-hash header on responses to signal which hash was used for that given request

2.0.0

• Refactored the way default hashing works (now includes request body by default, headers to turn off)
• Refactored the payload for preseeding to specify a request body

1.1.0

• Adding preseeding and many, many tests.

1.0.0

• Initial release