Support passing arguments and headers without specifying the AMQP type

[pma]

For known arguments in Queue.declare, Exchange.declare and Basic.consume, like "x-message-ttl" the API should accept arguments: ["x-message-ttl": 5000] and convert automatically to arguments: [{"x-message-ttl", :long, 5000}] as expected by the Erlang client.

This can also be applied to headers in Basic.publish, where the most common types (:longstr, :long and :bool) could be inferred from the value.

The format {name, type, value} can still be supported for all other cases.

@peck This would also address #4