Add Ring JSON middleware

add-json-wrappers.txt

application input: HttpInput (HTTP request body)       
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+--> wrap-json-body: Hash Map (deserialized from JSON)                 
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     +--> post-notes-handler: Hash Map (returns what it's been passed)
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          +--> response: Hash Map (a shell HTTP response)    
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               +--> wrap-json-response: JSON String (serialized from Hash Map)
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                    +--> application output