Refactor RR.rb; add 'if block_given?' to ctor of decoder & encoder to enable non-block use.
Prepend assignments in if clause with '!!' to clarify that the assignment is being made and is intentional.
Replace $n regex variables with use of MatchData object.
Minor refactoring.
Add failing test to show that method is not private.
Fix private declaration of class method.
Merge pull request #40 from keithrbennett/refactor-rr

Refactor RR.rb; add 'if block_given?' to ctor of decoder & encoder to en...