added local transactional api code
updated spec for Cheetah::Cheetah
simplify
added spec for SynchronousTransactionalMessenger
refactor. checkpoint
initialization options are optional
refactor send -> send_message
merge attachments
raise exception if send failed
successful send with resque

Signed-off-by: Wilfred Boayue <wil@moduscreate.com>
refactored. removed transactional message
better method naming
removed unneeded arguments
updated spec for resque transactional messenger
stub encode_attachments
tweak specs
update spec for transactional messenger
refactor
refactor. extract TransactionalCheetah
update readme