Bunny 0.7.3 fixes problem in parsing AMQP URL.

Tell the users what to use instead of Queue#publish. Version 0.7.1.

Conflicts:

	lib/bunny/version.rb

Updated CHANGELOG.

0.6.3.RC2 with corrected .gemspec

Extract version file, bump to 0.6.3.RC1 (read on)

Even though master version was 0.6.0 and the most recent release is 0.6.0
(not a very good practice to keep master version the same until release),
there are two tags in the repo: 0.6.1 and 0.6.2. I am not sure what to
do about this. Both tags date back to Dec 2009 or so.

So lets call it 0.6.3.RC1 and be done with it.

Release 0.6.2

Release 0.6.1