Use the Unicode replacement character instead of ? for invalid UTF8 chars.
Use String.scrub when available.
Use String.encode when String.scrub isn't available.
Add encoding declaration at top of file
Update .traivs.yml to include ree (ruby 1.8.7) and update
ruby 2.1.1 to 2.1.2
Make to_utf8! method a no-op for Ruby 1.8 which doesn't
support string encodings.
Use some path magic instead of require_relative which is unavailable
in Ruby 1.8
Make the invalid UTF8 test a no-op if Ruby 1.8 is used
(strings not encoding-aware)

whoops
Merge pull request #8 from zendesk/ggrossman/to_utf8

Use String.scrub! or String.encode! for fast fixing of invalid UTF8 and use Unicode replacement character instead of ? AND add support for Ruby 1.8