Made isNonBufferNonRegExpObject browser compatible.
Check that the Buffer global is a function before trying to use Buffer.isBuffer so we can be compatible with non-node.js environments.
RequestLine: Keep search and query as undefined when they haven't been assigned.
Message.toString: JSON.stringify a body stored as an object if the Content-Type is application/json.

Prevents "[object Object]" in the output.
Implemented HttpExchange class (request+response pair).
Implemented HttpConversation (a sequence of exchanges).
Fixed Message.prototype.toString behavior with no headers.
1.0.0