Merge from vendor branch TNF:

Merge from vendor branch TNF:
Initial import of ruby18-transaction-simple-1.4.0 as
misc/ruby-transaction-simple.

Transaction::Simple provides a generic way to add active transaction
support to objects.  The transaction methods added by this module will
work with most objects, excluding those that cannot be Marshal-ed
(bindings, procedure objects, IO instances, or singleton objects).