The previous design was base on these assumptions:
  RCRMQ instance only need to do either publish or consume
  RCRMQ instance only need to interact with one single queue

However, in order to perform RPC-like call, an instance will need to do both
publish and consume. In addition, publish and consume are not necessary
to the same queue. So, save queue name as single variable inside the
instance is not viable anymore.

Since publish doesn't have to do binding,
 separate binding make it cleaner and less trouble

user should explicitly call disconnect
Modify README regarding explicity disconnect call

Remove trailing whitespace
Add space between '+'

publish funtion:
 only make connection if it is not yet established
 only disconnect if there's no consumer using the same connection

consume function:
 only make connection if it is not yet established
 adding _consuming variable to keep tracking if the connection needs to be alive

with simple publish method