PROTON-381: Fixed encoding a Ruby symbol into a Data object.

The symbol is converted to a String before being added the Data
instance.

git-svn-id: https://svn.apache.org/repos/asf/qpid/proton/trunk@1509029 13f79535-47bb-0310-9956-ffa450edef68
PROTON-379: Added annotations property to Ruby Message class.

Added Rspec tests to verify. Also updated the send.rb and recv.rb
examples to use annotations.

git-svn-id: https://svn.apache.org/repos/asf/qpid/proton/trunk@1509030 13f79535-47bb-0310-9956-ffa450edef68