Updates following feedback from Alan Conway

git-svn-id: https://svn.apache.org/repos/asf/qpid/proton/branches/examples@1617478 13f79535-47bb-0310-9956-ffa450edef68
Update the first example to show sender created only once receiver is ready and describe why/where this may be a good idea

git-svn-id: https://svn.apache.org/repos/asf/qpid/proton/branches/examples@1617486 13f79535-47bb-0310-9956-ffa450edef68