added pn_list_pop
pool deliveries at the connection level; improved delivery refcounting semantics
PROTON-752: Release the GIL on blocking calls in Ruby.

Added a wrapper call for pn_messenger_recv, pn_messenger_send and
pn_messenger_work that calls the appropriate method for the version
of Ruby to release the GIL until the call returns in C.

Added to both CMakeLists.txt for the Ruby bindings, and also to the
extconf.rb file for the gem, a macro named RUBY## (where ## is 18, 19,
20 or 21 depending on the version of Ruby) to ensure the right API is
compiled into the extension since the API is different between 1.9 and
2.x and non-existent in 1.8, where it's a no-op.
PROTON-755: Require specific version of minitest for Ruby tests.

The require for the smoke tests now require a version between 4.7.0 and
not 5.0.
PROTON-755: Updated rspec tests to use the newer expect syntax

Rspec is moving away from monkey patching objects, and this new syntax
reflects that change. Updated the rspec tests to work with Rspec 2.4 and
3.x properly.
PROTON-755: Add SecureRandom for use by Ruby 1.8 tests
PROTON-755: Changed how the Data rspec test sets a single random character.

The new method is portable across versions of Ruby.
initial commit of psend/precv examples.
NO-JIRA: Remove unused internal sasl API
WIP: Change dispatcher interface (use transport as parameter
for frame handlers)
WIP: Change dispatcher interface (pass frametype and channel to
frame handlers)
WIP: Validate performative against frame type
WIP: Remove frame type from dispatcher
WIP: Remove scratch buffer from dispatcher.
WIP: Pass more of the frame directly into the frame handlers
WIP: Remove batch boolean from dispatcher
WIP: Move trace flags entirely to transport code
WIP: move around performative args
WIP: more constness
WIP: Move args from dispatcher->transport