Log Message:
Update ruby-amq-protocol to 1.2.0.

* Frame body on Ruby 1.9+ using bytes, not code points String#slice will only
  use byte slicing if the string is considered to be in ASCII.
* Replace broken link with an inline comment
* Adds specs to validate 8bit/16bit signed decoding
* Adds 8bit signed and 16bit signed integers to table decoder